00:00:00.000 [Music] 00:00:13.53900:00:13.549 welcome to this lecture the topic that 00:00:17.85900:00:17.869 will be discussed today is about the 00:00:21.32000:00:21.330 plate fin type heat exchangers this 00:00:25.64000:00:25.650 plate fin type heat exchanger is 00:00:27.23000:00:27.240 completely new type of exchanger we have 00:00:30.29000:00:30.300 not discussed in the previous lectures 00:00:34.88000:00:34.890 as you will be able to understand from 00:00:37.67000:00:37.680 the I mean following slides so before 00:00:41.92000:00:41.930 going into the details about the plate 00:00:44.54000:00:44.550 fin heat exchanger let us look where it 00:00:47.27000:00:47.280 belongs to in the classification of the 00:00:49.82000:00:49.830 heat exchangers so according to the 00:00:53.57000:00:53.580 classification and classification 00:00:56.27000:00:56.280 according to the construction we find 00:00:58.78900:00:58.799 that there was a class of exchanger 00:01:01.00900:01:01.019 where we had the extended surface heat 00:01:05.47900:01:05.489 transfer there was a class where we had 00:01:10.89900:01:10.909 heat exchangers with extended heat 00:01:13.37000:01:13.380 transfer surfaces and one of the 00:01:19.63000:01:19.640 derivative of this extended surface heat 00:01:22.76000:01:22.770 transfer is of plate fin type and that's 00:01:27.26000:01:27.270 what we call it plate fin type heat 00:01:30.77000:01:30.780 exchanger so if we look into the other 00:01:37.12000:01:37.130 classification where we will be able to 00:01:40.55000:01:40.560 find where it exactly it is belonging 00:01:45.80000:01:45.810 you will find that there is a 00:01:49.35900:01:49.369 classification based on the surface 00:01:51.73900:01:51.749 compactness and if we look into that 00:01:55.69000:01:55.700 classification we will find that there 00:01:59.14900:01:59.159 is the class of exchanger which is 00:02:01.39900:02:01.409 compact and that compactness is defined 00:02:05.14900:02:05.159 by a parameter beta which is defined as 00:02:10.16000:02:10.170 a demarcation is between the compactness 00:02:14.30000:02:14.310 and non compactness is 700 meter square 00:02:17.21000:02:17.220 per meter cube this classification has 00:02:21.32000:02:21.330 been 00:02:22.50000:02:22.510 mended by producer Artesia in his 00:02:26.22000:02:26.230 classification of heat exchanges in the 00:02:28.92000:02:28.930 heat exchangers thermo hydraulic 00:02:30.86900:02:30.879 fundamental and designed that is the 00:02:32.88000:02:32.890 book edited by ace Kaka and it all so we 00:02:38.13000:02:38.140 will be following this nomenclature of 00:02:40.85000:02:40.860 calling the heat exchanger as compact if 00:02:44.78900:02:44.799 the compactness factor beta is more than 00:02:48.86900:02:48.879 700 meter square per meter cube so this 00:02:53.81900:02:53.829 particular plate fin type of heat 00:02:56.06900:02:56.079 exchanger belongs to that category that 00:02:58.55900:02:58.569 it will be more than 400 meter square 00:03:02.33900:03:02.349 per 700 meters per per meter cube 00:03:04.94000:03:04.950 particularly this is a gas - fluid heat 00:03:09.72000:03:09.730 exchanger and in this region compactness 00:03:12.36000:03:12.370 is defined by 700 meter square per meter 00:03:15.30000:03:15.310 cube and we will define it as compact 00:03:18.62900:03:18.639 heat exchanger so if we now look into 00:03:22.80000:03:22.810 the hydraulic diameter from the 00:03:25.64900:03:25.659 hydraulic diameter point of view R if we 00:03:28.37900:03:28.389 look into the basic heat transfer 00:03:30.65900:03:30.669 equation we find that the heat 00:03:33.03000:03:33.040 transferred is basically related to the 00:03:35.52000:03:35.530 overall heat transfer coefficient and 00:03:37.40900:03:37.419 the delta T and this delta T L M 00:03:42.56900:03:42.579 basically the log mean temperature 00:03:43.94900:03:43.959 difference and if we divide both sides 00:03:46.92000:03:46.930 by the volume of the heat exchanger we 00:03:49.61900:03:49.629 find that it's giving us Q by V the heat 00:03:53.81900:03:53.829 transfer per unit volume that can be 00:03:55.94900:03:55.959 achieved it is a function of the overall 00:03:59.28000:03:59.290 heat transfer coefficient and not only 00:04:02.06900:04:02.079 that then we have a by P and delta T now 00:04:08.03900:04:08.049 this a by V the area per unit volume 00:04:10.74000:04:10.750 that's what is the beta factor that's 00:04:14.52000:04:14.530 what we are trying to define and then we 00:04:17.33900:04:17.349 also have the log mean temperature 00:04:18.87000:04:18.880 difference now this parameter the amount 00:04:23.49000:04:23.500 of heat that we can the heat load per 00:04:27.83900:04:27.849 unit delta T is basically we can find 00:04:31.29000:04:31.300 that it's a function of beta and V 00:04:34.74000:04:34.750 and also that you so if we have a very 00:04:39.72000:04:39.730 high beta value we can expect a small 00:04:44.88000:04:44.890 value of Delta V which will be you know 00:04:48.81000:04:48.820 if q by delta T is constant is remaining 00:04:52.35000:04:52.360 constant then for a given q by delta T 00:04:56.37000:04:56.380 we have you fixed and beta if we have a 00:05:00.36000:05:00.370 larger value we can expect that a 00:05:02.97000:05:02.980 smaller volume will be able to give us 00:05:05.97000:05:05.980 the desired effect so that means the 00:05:09.36000:05:09.370 heat exchanger can be made compact so if 00:05:13.38000:05:13.390 we look into that one so far we were 00:05:16.40000:05:16.410 looking into the tubular exchanger where 00:05:19.95000:05:19.960 the typical hydraulic diameter is of the 00:05:23.13000:05:23.140 order of this region where you see this 00:05:26.01000:05:26.020 is the I mean plane tubular sir and tube 00:05:31.23000:05:31.240 heat exchanger and on this side the 00:05:34.46000:05:34.470 louver train our etcetera strip filled 00:05:37.11000:05:37.120 these are basically the heat exchanger 00:05:39.27000:05:39.280 plate wind tie feat exchanges and the 00:05:42.21000:05:42.220 cryogenic heat exchangers are other type 00:05:45.21000:05:45.220 of matrix and other heat exchangers 00:05:47.13000:05:47.140 basically belong to that you know 00:05:49.53000:05:49.540 compact heat exchanger range so 00:05:52.02000:05:52.030 hydraulic diameter is of the order of 00:05:54.18000:05:54.190 this is where we have the hydraulic 00:05:56.37000:05:56.380 diameter and this is where we have the 00:06:00.26000:06:00.270 surface area density so nearly about 700 00:06:04.14000:06:04.150 is the demarcation between the 00:06:06.63000:06:06.640 compactness and the non compact heat 00:06:10.26000:06:10.270 exchanger so here somewhere here we have 00:06:13.08000:06:13.090 the that 500 600 700 that's the limiting 00:06:18.54000:06:18.550 line between the compact and non compact 00:06:21.00000:06:21.010 heat exchanger so basically this plate 00:06:25.38000:06:25.390 fin type heat exchanger belong to that 00:06:27.62000:06:27.630 compact heat exchanger with the typical 00:06:31.02000:06:31.030 surface area density more than 700 meter 00:06:33.99000:06:34.000 square per meter cube now if we look 00:06:39.60000:06:39.610 into the construction of this exchanger 00:06:42.27000:06:42.280 this is a real-time heat exchanger just 00:06:46.74000:06:46.750 to show you how it 00:06:48.51000:06:48.520 looks like we should actually have a 00:06:50.93900:06:50.949 length scale it's a you can understand 00:06:54.83900:06:54.849 that this is the length and we have one 00:06:58.17000:06:58.180 fluid flowing from one end to the other 00:07:00.39000:07:00.400 end directly from this end to this end 00:07:03.51000:07:03.520 and another fluid it is entering here it 00:07:07.49900:07:07.509 has to exit it can come out from this 00:07:10.52900:07:10.539 end it can also come out from this end 00:07:12.57000:07:12.580 so it is also I mean this is another I 00:07:17.36900:07:17.379 mean advantage or you can say the 00:07:20.01000:07:20.020 characteristics of this plate fin type 00:07:22.14000:07:22.150 heat exchanger where multiple exit our 00:07:25.82000:07:25.830 intermediate entry and exit can be 00:07:29.30900:07:29.319 possible in this type of heat exchanger 00:07:31.89000:07:31.900 okay so in another picture in a 00:07:37.20000:07:37.210 pictorial view I will show you here this 00:07:39.87000:07:39.880 is another plate fin type heat exchanger 00:07:41.85000:07:41.860 you can see glimpse of the fins these 00:07:45.14900:07:45.159 are the fins we're sorry we will be 00:07:50.45000:07:50.460 discussing about this geometry later on 00:07:53.49000:07:53.500 so this is the cross flow type plate fin 00:07:55.95000:07:55.960 type heat exchanger where this is made 00:07:58.46900:07:58.479 of alum bridged aluminium there are two 00:08:01.95000:08:01.960 terms bridged and aluminium plate fin 00:08:05.18900:08:05.199 type heat exchanger this is also a plate 00:08:07.55900:08:07.569 winter heat exchanger which is made of 00:08:09.87000:08:09.880 aluminium and that aluminium is bridged 00:08:13.64900:08:13.659 with each other so that it is a special 00:08:17.70000:08:17.710 type of break phonetics engine which is 00:08:20.82000:08:20.830 a braised aluminium plate fin heat 00:08:22.98000:08:22.990 exchanger so we'll talk about this in 00:08:25.92000:08:25.930 details first of all let us have a look 00:08:29.70000:08:29.710 into the details of this why we go for 00:08:34.44000:08:34.450 aluminium why do we go for brazing of it 00:08:37.88900:08:37.899 so first of all this aluminium is one of 00:08:43.80000:08:43.810 the I mean good thermal conductivity 00:08:46.59000:08:46.600 material with light witness I mean this 00:08:50.34000:08:50.350 kind of exchangers are widely used in 00:08:52.74000:08:52.750 automobiles or in aircraft so this way 00:08:56.73000:08:56.740 to strength ratio of this material is 00:08:59.18900:08:59.199 always and looked after I mean 00:09:01.74000:09:01.750 is a parameter which you always look for 00:09:04.62000:09:04.630 and we will understand that the bridging 00:09:08.40000:09:08.410 is the only option particularly for the 00:09:10.62000:09:10.630 type of fiends we are going to be join 00:09:12.30000:09:12.310 in case of a platform type physics near 00:09:15.48000:09:15.490 we cannot do the regular welding though 00:09:17.67000:09:17.680 aluminium welding it's possible we 00:09:20.19000:09:20.200 cannot do the welding of field surfaces 00:09:24.30000:09:24.310 with the plates manually so we have to 00:09:28.02000:09:28.030 go for a automatic joining of the plate 00:09:33.87000:09:33.880 with the fins which we'll be talking 00:09:36.78000:09:36.790 later on and so this particular 00:09:43.23000:09:43.240 properties like low I mean high sorry 00:09:48.72000:09:48.730 the high strength-to-weight ratio this 00:09:52.56000:09:52.570 weight is small and it's strength is 00:09:54.78000:09:54.790 high and it's a having moderately good 00:09:58.26000:09:58.270 thermal conductivity so we go for it and 00:10:01.35000:10:01.360 also it it's it can be bridged so that's 00:10:04.53000:10:04.540 another favorable parameter particularly 00:10:08.46000:10:08.470 we go for the aluminium three thousand 00:10:11.43000:10:11.440 three 3000 series particularly this is 00:10:14.91000:10:14.920 the other than any element aluminium 00:10:18.59000:10:18.600 particularly it is a manganese based and 00:10:23.34000:10:23.350 it's percentage is about 10 sorry 1 to 00:10:26.55000:10:26.560 1.5 percentage of manganese it will be 00:10:29.82000:10:29.830 there and it's the solid as this 643 00:10:33.12000:10:33.130 degree centigrade so if we have a plate 00:10:36.75000:10:36.760 and we will be connecting the fins on 00:10:41.13000:10:41.140 top of it and it is like this will be 00:10:44.52000:10:44.530 joining this is the kind of fiend we 00:10:47.40000:10:47.410 will be joining and this is the plate 00:10:51.18000:10:51.190 material so on top of it we want to have 00:10:55.07900:10:55.089 a kind of filler material or the I mean 00:10:59.49000:10:59.500 which is this this is the bridging 00:11:02.67000:11:02.680 material this bridging material is 00:11:06.05000:11:06.060 aluminium plus 7 percent silicon so it's 00:11:11.07000:11:11.080 melting point when as soon as we add 00:11:15.04000:11:15.050 7% silicon it becomes the five ninety 00:11:18.13000:11:18.140 degree whereas the solidus of this 00:11:21.67000:11:21.680 parent material this is six forty three 00:11:25.44900:11:25.459 degree centigrade so that means this 00:11:28.75000:11:28.760 filler material will melt fast but this 00:11:33.04000:11:33.050 parent material will not melt at that 00:11:36.31000:11:36.320 time but this difference in temperature 00:11:39.16000:11:39.170 is very small so we can understand that 00:11:43.48000:11:43.490 we need a very very precise temperature 00:11:48.94000:11:48.950 fairness I mean fairness the temperature 00:11:51.55000:11:51.560 control in the furnace is very very 00:11:53.44000:11:53.450 stringent and we have to maintain the 00:11:56.19900:11:56.209 temperature of the furnace basically we 00:11:58.09000:11:58.100 will talk about the manufacturing of 00:11:59.65000:11:59.660 that bridged aluminium plate phonetics 00:12:02.23000:12:02.240 we will discuss in details at that time 00:12:05.40000:12:05.410 so we need to maintain the temperature 00:12:09.57900:12:09.589 of the furnace so that this parent 00:12:12.88000:12:12.890 material should not melt I mean it will 00:12:17.56000:12:17.570 of course ensure a good we need to 00:12:20.31900:12:20.329 ensure a good bridging between the frame 00:12:23.86000:12:23.870 and the plate but at the same time we 00:12:27.57900:12:27.589 also need to ensure that there is no you 00:12:30.73000:12:30.740 know a kind of hole or formation of any 00:12:34.03000:12:34.040 leakage so that one fluid which is 00:12:36.46000:12:36.470 flowing on this side and the fluid 00:12:38.56000:12:38.570 flowing on this side should not leak and 00:12:40.92000:12:40.930 that's what we need to ensure so 00:12:46.59000:12:46.600 generally it is the vacuum bridged it 00:12:49.81000:12:49.820 these units are made in vacuum brazing 00:12:51.57900:12:51.589 furnace so we need a very stringent 00:12:55.35000:12:55.360 temperature requirement for 00:12:57.25000:12:57.260 manufacturing this kind of heat 00:12:59.05000:12:59.060 exchangers so we'll come to that part 00:13:01.00000:13:01.010 later 00:13:02.67000:13:02.680 so here is the exploded view for a 00:13:07.42000:13:07.430 particular layer of the plate fin type 00:13:10.81000:13:10.820 heat exchanger we have one layer of 00:13:15.56900:13:15.579 primary heat transfer surface area 00:13:18.06900:13:18.079 basically this is an as I told in the 00:13:21.13000:13:21.140 initially that this is an extended type 00:13:24.10000:13:24.110 heat transfer surface so according to 00:13:27.43000:13:27.440 that classification 00:13:29.11000:13:29.120 we have a primary heat transfer surface 00:13:31.56900:13:31.579 area and then this is what's the primary 00:13:34.96000:13:34.970 heat transfer surface area now we have 00:13:37.54000:13:37.550 another primary heat transfer surface 00:13:39.36900:13:39.379 area on this side and between this 00:13:42.48900:13:42.499 primary heat transfer surface area we 00:13:45.10000:13:45.110 have the extended heat transfer surface 00:13:47.59000:13:47.600 area or the field so in between these 00:13:52.11900:13:52.129 two plates or the primary heat transfer 00:13:55.23900:13:55.249 surface area we have some fins or 00:13:59.04000:13:59.050 extended heat transfer surface so now 00:14:02.53000:14:02.540 the purpose of this fin is and here what 00:14:08.25900:14:08.269 we have is something called sidebar this 00:14:11.67900:14:11.689 is what a sidebar on this side also it 00:14:14.98000:14:14.990 is a sidebar so that means it's 00:14:17.76900:14:17.779 basically like this that we want to make 00:14:20.82900:14:20.839 a channel this channel is made of one 00:14:24.97000:14:24.980 primary surface area another primary 00:14:27.46000:14:27.470 surface area in between what we have is 00:14:31.23000:14:31.240 the film this film is serving both the 00:14:37.56900:14:37.579 purposes of or it has double I mean the 00:14:44.07900:14:44.089 purpose of this fin is basically to 00:14:47.07900:14:47.089 provide extra or extended heat transfer 00:14:50.71000:14:50.720 surface area at the same time it gives a 00:14:54.48900:14:54.499 mechanical stability or construction 00:15:00.51900:15:00.529 stability like it gives some strength to 00:15:05.49900:15:05.509 the construction so that under pressure 00:15:08.82900:15:08.839 this will not bulge so this mechanical 00:15:13.11900:15:13.129 stability of this one will also be 00:15:15.54000:15:15.550 purpose for this one so now you can 00:15:18.16000:15:18.170 understand that each of this surface is 00:15:21.18900:15:21.199 to be adhered to this plate and this one 00:15:24.75900:15:24.769 has to be adhered to this plate to have 00:15:27.10000:15:27.110 a good thermal joint we need a good 00:15:31.74900:15:31.759 thermal contact between these two 00:15:33.81900:15:33.829 otherwise there would be when the heat 00:15:35.71000:15:35.720 is getting transferred so there would be 00:15:37.78000:15:37.790 a resistance between this fin and the 00:15:40.03000:15:40.040 plate so that is not desirable we 00:15:42.67000:15:42.680 want this fiend to be completely at as 00:15:46.51000:15:46.520 thermally to this upper surface so we 00:15:49.63000:15:49.640 need a good bonding between this point 00:15:51.94000:15:51.950 this point this point and in fact all 00:15:55.42000:15:55.430 the surfaces should be adhere to this 00:16:00.42000:16:00.430 primary heat transfer surface area and 00:16:03.57000:16:03.580 this fins are to be attached so it is 00:16:07.32000:16:07.330 understandable that it is not possible 00:16:10.38000:16:10.390 for someone to make physical joint 00:16:14.92000:16:14.930 because he first of all it will not be 00:16:17.05000:16:17.060 accessible even if it is not accessible 00:16:19.12000:16:19.130 even if it is the accessible it is 00:16:21.13000:16:21.140 impossible to make or ensure that each 00:16:24.46000:16:24.470 and every point of it is joined with the 00:16:27.28000:16:27.290 primary surface area now as you can 00:16:31.32900:16:31.339 understand that we have two primary 00:16:34.15000:16:34.160 surface area in between we have the 00:16:37.75000:16:37.760 field and now imagine this is the cross 00:16:42.49000:16:42.500 sectional area and we have say a fluid 00:16:45.88000:16:45.890 flowing from this end to the other end 00:16:48.87000:16:48.880 so we have to ensure that the fluid is 00:16:52.84000:16:52.850 not spilling over from this side or this 00:16:56.35000:16:56.360 side it should not go out of this one so 00:17:00.46000:17:00.470 what we need to do for this purpose that 00:17:03.40000:17:03.410 we should have a kind of side bar on 00:17:07.80900:17:07.819 both lines so this will be we will put a 00:17:13.89000:17:13.900 barricade on this side and another 00:17:17.98000:17:17.990 barricade on this side so we are 00:17:20.91900:17:20.929 confining the liquid within this zone 00:17:24.15000:17:24.160 and this zone is created by this one 00:17:30.07000:17:30.080 where we have the primary surface area 00:17:32.41000:17:32.420 and the field and it is bounded by two 00:17:36.49000:17:36.500 side but so this is the exploded view 00:17:40.51000:17:40.520 for a particular layer and so we can 00:17:45.10000:17:45.110 expect that on top of it 00:17:47.65000:17:47.660 we will put another layer so that will 00:17:50.86000:17:50.870 form the this is an exploded view of the 00:17:56.30000:17:56.310 to layer one so here what we have is one 00:18:00.59000:18:00.600 fluid this is the primary surface area 00:18:02.99000:18:03.000 this is another primary surface area 00:18:06.28000:18:06.290 this is these are the primary surface 00:18:08.84000:18:08.850 areas and we have one fluid flowing from 00:18:13.73000:18:13.740 this end to this end so these are the 00:18:16.85000:18:16.860 extended heat transfer surface area fin 00:18:19.34000:18:19.350 and now imagine we have put on top of it 00:18:24.62000:18:24.630 another layer where this is the plate 00:18:29.15000:18:29.160 which is the primary area separating 00:18:31.67000:18:31.680 this fluid to mix with this fluid this 00:18:34.58000:18:34.590 fluid is entering from this end and we 00:18:39.23000:18:39.240 have another separating plate on this 00:18:41.57000:18:41.580 side so for this fluid this is the side 00:18:46.31000:18:46.320 bar for this fluid we have this side bar 00:18:50.21000:18:50.220 and on this side we have another side 00:18:52.73000:18:52.740 bar so that between this two primary 00:18:57.11000:18:57.120 surfaces we have fin and two plates two 00:19:02.60000:19:02.610 sidebars so this is one channel for this 00:19:06.11000:19:06.120 fluid similarly on the other side what 00:19:09.47000:19:09.480 we have is this primary surface area and 00:19:13.57000:19:13.580 then we have this is the primary surface 00:19:18.38000:19:18.390 area and what we have here is I'm sorry 00:19:24.10000:19:24.110 this is one surface area then we have 00:19:31.10000:19:31.110 another surface area here this is the 00:19:33.89000:19:33.900 confinement this is the side but these 00:19:36.53000:19:36.540 are the two side bar and these are the 00:19:38.45000:19:38.460 fins so this whole unit becomes an 00:19:41.54000:19:41.550 exploded view and this is for this 00:19:44.90000:19:44.910 particular channel is meant for this 00:19:47.27000:19:47.280 plate so like this we have this fluid 00:19:51.65000:19:51.660 getting distributed between several 00:19:54.53000:19:54.540 layers and this is for if it is this 00:19:57.92000:19:57.930 layer is designated for this channel and 00:20:00.35000:20:00.360 the alternative will again be for this 00:20:03.26000:20:03.270 fluid say if we call it fluid number one 00:20:05.54000:20:05.550 and this is the fluid two we have 00:20:10.04000:20:10.050 this channel designated for free to the 00:20:13.25000:20:13.260 next channel will be designated for the 00:20:15.95000:20:15.960 fluid one so like that we have this is a 00:20:20.45000:20:20.460 two fluid stream heat exchanger and as 00:20:23.60000:20:23.610 you can understand that each fluid flow 00:20:26.45000:20:26.460 is taking place at 90 degree so it is a 00:20:29.93000:20:29.940 cross flow arrangement so when we talk 00:20:33.29000:20:33.300 about the flow arrangement will come in 00:20:35.06000:20:35.070 details so this is the exploded view 00:20:37.46000:20:37.470 when like this we make you know a stack 00:20:40.70000:20:40.710 of the heat exchanger and then we go for 00:20:44.15000:20:44.160 the complete heat exchanger matrix or 00:20:49.22000:20:49.230 something like that so here what we have 00:20:53.12000:20:53.130 is the plate this is the plate 00:20:56.30000:20:56.310 this is sidebar these are the frame and 00:21:00.44000:21:00.450 as the name suggests the plate fin comes 00:21:04.79000:21:04.800 from this nomenclature I mean this no 00:21:07.94000:21:07.950 ventilation this is fin this is plate 00:21:10.61000:21:10.620 and as a whole this unit becomes the 00:21:13.79000:21:13.800 plate fin heat exchanger so this is a 00:21:21.14000:21:21.150 typical bridged aluminium plate fin heat 00:21:24.02000:21:24.030 exchanger we can have a look into this 00:21:27.82000:21:27.830 small video this is a bridged aluminium 00:21:36.62000:21:36.630 plate fin heat exchanger 00:21:46.24000:21:46.250 so here as you can understand that this 00:21:50.26000:21:50.270 is the sidebar we are not able to see 00:21:53.35000:21:53.360 this particular area so the fins are 00:21:57.61000:21:57.620 located at this point these are the 00:22:00.07000:22:00.080 fields so this channel through which the 00:22:04.72000:22:04.730 fluid is flowing you will find that this 00:22:07.36000:22:07.370 is blocked at this end and this is 00:22:09.97000:22:09.980 blocked at this end so that the fluid is 00:22:12.90900:22:12.919 flowing in this direction so this is 00:22:16.69000:22:16.700 basically nothing but the rectangular 00:22:19.68000:22:19.690 Hollow header which is allowing the 00:22:23.40900:22:23.419 fluid to come on this side and allow the 00:22:26.91900:22:26.929 fluid to flow through this end and this 00:22:31.68000:22:31.690 black coloured one whereas that white 00:22:37.81000:22:37.820 one is basically nothing but the 00:22:42.18000:22:42.190 sidebars so if we look into the video 00:22:53.19000:22:53.200 this is the other side we will come to 00:23:01.77000:23:01.780 we look into this retells so now you see 00:23:05.32000:23:05.330 this is what is the sidebar and the 00:23:11.74000:23:11.750 corresponding site on the other end I 00:23:14.40900:23:14.419 mean just we have come from that into 00:23:17.35000:23:17.360 this end you find that this is the plate 00:23:22.48000:23:22.490 or the primary area and with that 00:23:25.69000:23:25.700 primary area between this two primary 00:23:28.00000:23:28.010 area we have the fins there adhere to 00:23:32.38000:23:32.390 each other I mean with the it is 00:23:34.77900:23:34.789 breached at this point at this point and 00:23:37.79900:23:37.809 this is particularly this is an oily 00:23:40.99000:23:41.000 film and here we have a sidebar so this 00:23:47.04900:23:47.059 is a site but if you look at this end 00:23:49.77900:23:49.789 for this particular thing this geometry 00:23:53.74000:23:53.750 this end you have it is not visible at 00:23:56.91900:23:56.929 this position this end and this 00:23:58.85000:23:58.860 it is blocked so these are the side 00:24:01.46000:24:01.470 birds so when the fluid is flowing in 00:24:04.46000:24:04.470 this direction the fluid will flow this 00:24:07.52000:24:07.530 channels through these channels through 00:24:10.03900:24:10.049 this channel this channel it will flow 00:24:11.93000:24:11.940 through and it will not pass odd mix 00:24:16.01000:24:16.020 with the sidebar are this is the site 00:24:21.50000:24:21.510 but this is another sidebar these are 00:24:23.84000:24:23.850 the side verse and the fluid is not able 00:24:27.98000:24:27.990 to mix with the fluid flowing on the 00:24:30.74000:24:30.750 other side through this channel so 00:24:33.14000:24:33.150 basically this is a again a cross flow 00:24:35.39000:24:35.400 type heat exchanger where we have both 00:24:39.62000:24:39.630 the fluids I mean not mixed it is 00:24:42.91900:24:42.929 unmixed both the fluids unmixed and this 00:24:46.78900:24:46.799 is basically you can understand that 00:24:49.64000:24:49.650 this is a slightly longer length than 00:24:54.11000:24:54.120 this particular one so this is wider 00:24:57.23000:24:57.240 this is smaller okay so now what are the 00:25:06.62000:25:06.630 advantage of this particular type of 00:25:08.90000:25:08.910 heat exchangers the advantage of bridged 00:25:12.95000:25:12.960 aluminium plate fin heat exchanger as we 00:25:14.90000:25:14.910 have discussed earlier that it is the 00:25:16.52000:25:16.530 compact heat exchanger so it has a very 00:25:19.82000:25:19.830 high heat transfer surface area density 00:25:21.95000:25:21.960 and it is most of the time it is more 00:25:26.33000:25:26.340 than 700 meter square per meter cube 00:25:28.66900:25:28.679 that means we get very very good 00:25:31.81000:25:31.820 compactness in fact we will find some of 00:25:34.76000:25:34.770 the cryogenic heat exchangers they are 00:25:37.10000:25:37.110 quite really big but if they were not 00:25:40.46000:25:40.470 compact they would have been still 00:25:42.35000:25:42.360 bigger in size so as compared to this 00:25:47.95000:25:47.960 surface area density we have relatively 00:25:51.40900:25:51.419 low pressure drop any heat exchanger 00:25:55.90900:25:55.919 designer they will try to make a heat 00:25:59.51000:25:59.520 exchanger where we have high heat 00:26:04.03900:26:04.049 transfer but the pressure drop penalty 00:26:07.10000:26:07.110 is comparatively smaller so here we have 00:26:11.03000:26:11.040 the 00:26:12.46000:26:12.470 thermal performance desirable thermal 00:26:15.32000:26:15.330 performance of the heat exchanger but 00:26:17.69000:26:17.700 not very high at the cost of large 00:26:22.25000:26:22.260 pressure drop so it is having a moderate 00:26:25.01000:26:25.020 pressure drop and since it is made of 00:26:28.76000:26:28.770 aluminium we have the low weight up for 00:26:33.44000:26:33.450 this heat exchanger and it is not really 00:26:36.65000:26:36.660 very costly though the particularly the 00:26:41.35000:26:41.360 fabrication technique determines its 00:26:44.36000:26:44.370 cost and the number of units which are 00:26:47.48000:26:47.490 made on the size of the heat exchanger 00:26:49.43000:26:49.440 that determines its cost and we have I 00:26:53.72000:26:53.730 mean another big advantage of this 00:26:56.87000:26:56.880 particular type of heat exchanger is 00:26:58.58000:26:58.590 that it can handle large number of 00:27:01.58000:27:01.590 stream in a single unit so basically 00:27:05.78000:27:05.790 that makes this plate fin type heat 00:27:09.71000:27:09.720 exchanger multi stream heat exchanger so 00:27:15.11000:27:15.120 it handles multiple streams multi stream 00:27:20.02000:27:20.030 heat exchanger so multiple stream heat 00:27:23.42000:27:23.430 exchanger accommodating multiple streams 00:27:26.75000:27:26.760 within a single unit is obviously 00:27:30.25000:27:30.260 advantageous so we get well later on see 00:27:34.76000:27:34.770 how this plate fin heat exchangers allow 00:27:37.82000:27:37.830 the handling of multiple strings within 00:27:40.91000:27:40.920 the same unit then we also have the 00:27:45.68000:27:45.690 advantage particularly with respect to 00:27:48.29000:27:48.300 this plate fin type heat exchanger is 00:27:50.78000:27:50.790 that we have the intermediate entry and 00:27:54.20000:27:54.210 exit of the fluid streams so that gives 00:27:57.02000:27:57.030 up big advantage or flexibility in the 00:28:02.14000:28:02.150 handling of the fluid streams so not 00:28:05.06000:28:05.070 only it handles multiple streams 00:28:07.07000:28:07.080 it also helps intermediate entry and 00:28:10.28000:28:10.290 exit of the fluid streams in the heat 00:28:12.53000:28:12.540 exchanger so next is its application 00:28:19.58000:28:19.590 where are the places where we find its 00:28:22.31000:28:22.320 application so in most of the crisis 00:28:25.67000:28:25.680 unique process plants these days 00:28:27.62000:28:27.630 cryogenic liquefaction liquefaction 00:28:29.90000:28:29.910 plants then air separation plants then 00:28:33.35000:28:33.360 we have the regenerators and as I told 00:28:36.38000:28:36.390 you this is the air separation plant we 00:28:39.02000:28:39.030 have the main heat exchangers the where 00:28:42.59000:28:42.600 the air is being handled and then we 00:28:45.59000:28:45.600 have the condenser reboiler in between 00:28:49.07000:28:49.080 the double column unit so the condenser 00:28:52.46000:28:52.470 reboiler earlier used to be a shell and 00:28:56.42000:28:56.430 tube type or tubular exchanger this days 00:28:59.42000:28:59.430 you will find frequently that these are 00:29:01.73000:29:01.740 replaced by plate fin type heat 00:29:05.48000:29:05.490 exchangers so most of the cryogenic 00:29:08.87000:29:08.880 process plants heat exchangers are of 00:29:12.64000:29:12.650 very high effectiveness and most of the 00:29:16.43000:29:16.440 time we'll look for heat exchanger 00:29:19.37000:29:19.380 effectiveness around and I mean 0.92 95 00:29:25.43000:29:25.440 or so I mean otherwise some of the 00:29:31.52000:29:31.530 processes will I mean will not at all 00:29:34.64000:29:34.650 start if the heat exchanger 00:29:35.99000:29:36.000 effectiveness is very small so we have 00:29:39.50000:29:39.510 very stringent requirement for the heat 00:29:42.26000:29:42.270 exchanger effectiveness in case of 00:29:44.21000:29:44.220 cryogenic heat exchangers so we find 00:29:47.21000:29:47.220 that bridge development between heat 00:29:49.85000:29:49.860 exchangers amid that requirement of high 00:29:54.26000:29:54.270 effectiveness heat exchangers in 00:29:56.09000:29:56.100 cryogenic engineering moreover in 00:29:58.73000:29:58.740 aircrafts the requirements are slightly 00:30:01.55000:30:01.560 different here you will find that the 00:30:04.25000:30:04.260 heat exchanger effectiveness is not that 00:30:06.08000:30:06.090 high but it need to be a very very light 00:30:09.38000:30:09.390 weight and there the air conditioning 00:30:13.25000:30:13.260 hydraulic and lube oil coolers in the 00:30:16.61000:30:16.620 ram air cooling etcetera are done in 00:30:19.40000:30:19.410 case of I mean heat exchangers are made 00:30:22.49000:30:22.500 out of a bridged aluminium and sometime 00:30:25.25000:30:25.260 it is bridged stainless steel to meet 00:30:28.82000:30:28.830 the high temperature requirement of the 00:30:32.56000:30:32.570 handling high temperature requirement in 00:30:35.69000:30:35.700 the air crafts we find there some of the 00:30:38.12000:30:38.130 exchanges are May 00:30:39.52900:30:39.539 of stainless till then in automatic 00:30:43.00900:30:43.019 automobile radiators we find that 00:30:46.96000:30:46.970 frequently these days we are using the 00:30:49.94000:30:49.950 bridged aluminum plate fin type of heat 00:30:52.03900:30:52.049 exchangers and in chemical process 00:30:54.52900:30:54.539 plants where we have gas to gas service 00:30:58.15900:30:58.169 this is particularly important why do we 00:31:01.75900:31:01.769 go for a gas to gas 00:31:03.91900:31:03.929 I mean heat exchanger I mean why should 00:31:06.56000:31:06.570 we restrict it to the gas to gas as you 00:31:09.49900:31:09.509 can understand that the hydraulic 00:31:11.62900:31:11.639 diameter or the fin passage is being 00:31:14.14900:31:14.159 very small so we have a requirement of I 00:31:18.79900:31:18.809 mean basically clean fluid so if any 00:31:24.83000:31:24.840 kind of darts or I mean contamination is 00:31:29.18000:31:29.190 there in the process stream you will 00:31:31.66900:31:31.679 find that those flow passages are 00:31:34.43000:31:34.440 getting choked and if anything such 00:31:37.99900:31:38.009 happens often it is not possible to 00:31:42.22900:31:42.239 clean it if it is not getting resolved 00:31:45.49900:31:45.509 through some of the chemicals we will 00:31:48.22900:31:48.239 find it is not possible to get it 00:31:50.21000:31:50.220 cleaned so this cleanliness of the 00:31:54.95000:31:54.960 process with streams is one of the 00:31:57.79900:31:57.809 primary requirement for this kind of 00:32:01.51900:32:01.529 heat exchangers and in chemical process 00:32:04.54900:32:04.559 plant where the gas and gas to gas 00:32:07.72900:32:07.739 particularly service where it is mostly 00:32:10.54900:32:10.559 clean and it will find that bridged 00:32:14.74900:32:14.759 aluminium plate wing type heat 00:32:16.24900:32:16.259 exchangers are frequently in use another 00:32:20.02900:32:20.039 while talking about the limitations or I 00:32:23.06000:32:23.070 mean applications of this bridge to 00:32:24.85900:32:24.869 aluminium plate fin type of heat 00:32:26.38900:32:26.399 exchangers we can understand that when 00:32:31.87900:32:31.889 it is bridged aluminium plate fin heat 00:32:33.76900:32:33.779 exchanger obviously it's high 00:32:35.57000:32:35.580 temperature requirement is limited it 00:32:38.21000:32:38.220 cannot go more than some thing like you 00:32:41.18000:32:41.190 know it's solid as temperature similarly 00:32:43.43000:32:43.440 not very close to the same solid as 00:32:45.85900:32:45.869 temperature but on the other hand in 00:32:48.97900:32:48.989 that case you need to go for the 00:32:50.74900:32:50.759 stainless steel type 00:32:52.85000:32:52.860 is stainless steel between type heat 00:32:54.86000:32:54.870 exchanger and motor but as you can 00:32:58.64000:32:58.650 understand from the construction of this 00:33:00.53000:33:00.540 kind of plate fin type heat exchanger 00:33:01.94000:33:01.950 that probably you cannot go for very 00:33:06.32000:33:06.330 very high pressure 00:33:07.76000:33:07.770 I mean when the process streams are of 00:33:09.89000:33:09.900 very high pressure we cannot really 00:33:12.11000:33:12.120 recommend the use of this plate fin type 00:33:14.93000:33:14.940 physics nears so it is the moderate to 00:33:17.99000:33:18.000 low pressure when it is the exchanges 00:33:21.56000:33:21.570 are I mean are of very good use so now 00:33:27.14000:33:27.150 know the part of the pin types I mean I 00:33:32.84000:33:32.850 mean there are why should there be 00:33:36.38000:33:36.390 anything and particularly when we talk 00:33:39.91900:33:39.929 about the fin or the extended heat 00:33:42.91900:33:42.929 transfer surface these fins as I told 00:33:46.01000:33:46.020 you it gives up mechanical stability and 00:33:49.12000:33:49.130 also it gives extended heat transfer 00:33:51.79900:33:51.809 surface so if we look at that again that 00:33:56.33000:33:56.340 equation if we look at QV calls to you 00:33:59.51000:33:59.520 into a into delta T often this delta T L 00:34:04.88000:34:04.890 M is dictated by the process stream we 00:34:10.52000:34:10.530 cannot really have a control on this log 00:34:14.30000:34:14.310 mean temperature difference we may not 00:34:16.73000:34:16.740 have control on much control on the 00:34:19.31000:34:19.320 overall heat transfer coefficient so we 00:34:21.64900:34:21.659 have to manage with this area heat 00:34:25.70000:34:25.710 transfer surface area so we augmented 00:34:29.06000:34:29.070 the heat transfer surface area with the 00:34:32.84000:34:32.850 extended surface heat transfer so this 00:34:36.02000:34:36.030 is what is this fin the role of this 00:34:38.38900:34:38.399 frame is to enhance the heat transfer 00:34:41.51000:34:41.520 surface area along with the mechanical 00:34:44.27000:34:44.280 stability or the construction stability 00:34:47.59900:34:47.609 so not only that it has a third purpose 00:34:53.37900:34:53.389 when we have a straight rectangular 00:34:56.54000:34:56.550 plane rectangular fin we find that the 00:34:59.72000:34:59.730 flow will be developed within a few 00:35:03.25000:35:03.260 millimeter or depending on its size 00:35:06.92000:35:06.930 the entrance length after the entrance 00:35:09.44000:35:09.450 length the flow is fully developed and 00:35:11.66000:35:11.670 there is constant heat transfer 00:35:14.60000:35:14.610 coefficient for the entire region now 00:35:17.39000:35:17.400 what we need to do is that the I mean if 00:35:21.59000:35:21.600 we want to change the heat transfer 00:35:25.25000:35:25.260 coefficient I mean if it is a regular 00:35:29.27000:35:29.280 plain regular or rectangular plane fin 00:35:32.15000:35:32.160 channel so we don't have that option of 00:35:35.59000:35:35.600 breaking that boundary layer so that is 00:35:39.41000:35:39.420 also true in case of plain trapezoidal 00:35:42.68000:35:42.690 fin so after certain and translate you 00:35:46.40000:35:46.410 find that the flow is fully developed 00:35:48.02000:35:48.030 and there won't be any change in the 00:35:51.79000:35:51.800 there is no change in the fringe 00:35:55.67000:35:55.680 geometry I mean there is no change in 00:35:58.01000:35:58.020 the heat transfer coefficient because of 00:36:00.02000:36:00.030 it is fully developed but in case of 00:36:04.48000:36:04.490 stripping geometry we find that the flow 00:36:09.11000:36:09.120 is the it is slightly offset as we can 00:36:13.91000:36:13.920 call it an offset stripping this is a 00:36:18.58000:36:18.590 slightly after certain length this is 00:36:21.17000:36:21.180 called the Lance length after this Lance 00:36:23.99000:36:24.000 length this is known as Lance length 00:36:27.56000:36:27.570 after the Lance length this as you can 00:36:30.92000:36:30.930 understand that as if the flow passage 00:36:34.79000:36:34.800 has been shifted it has you know it was 00:36:37.97000:36:37.980 flowing like this now suddenly the path 00:36:41.36000:36:41.370 has been broken and you know it has been 00:36:43.70000:36:43.710 shifted like this 00:36:44.93000:36:44.940 this channel is been shifted so after 00:36:48.38000:36:48.390 coming the flow after coming over here 00:36:50.87000:36:50.880 it finds that there is another you know 00:36:56.08000:36:56.090 fresh generation of the fresh boundary 00:37:00.59000:37:00.600 layer at this point similarly again 00:37:03.68000:37:03.690 after going at this point it will find 00:37:06.50000:37:06.510 that there is the flow has to be 00:37:08.51000:37:08.520 developed at this point so like that the 00:37:11.33000:37:11.340 flow is getting developed I mean at 00:37:13.76000:37:13.770 every regular interval and in this 00:37:16.25000:37:16.260 offset stripping we this purpose of this 00:37:20.66000:37:20.670 officer Tiffin is to not only enhance 00:37:23.63000:37:23.640 the heat transfer surface area not only 00:37:26.21000:37:26.220 give the mechanical stability it also 00:37:29.03000:37:29.040 enhances the heat transfer surface area 00:37:32.39000:37:32.400 just because of the Finn construction so 00:37:36.70000:37:36.710 another thing is of I mean use that is 00:37:41.36000:37:41.370 wavy Finn in this type of field it is 00:37:45.71000:37:45.720 the continuous wind here you can see 00:37:47.93000:37:47.940 there is a discontinuity in the field we 00:37:50.99000:37:51.000 are interrupting the FINA tricular 00:37:52.79000:37:52.800 interval but in this type this is the 00:37:55.94000:37:55.950 continuous fin geometry but still it's 00:37:59.15000:37:59.160 the waviness Gibbs as the desired flow 00:38:03.29000:38:03.300 separation at regular interval and 00:38:05.74000:38:05.750 breaking up the boundary layer at 00:38:08.06000:38:08.070 regular interval causing enhancement in 00:38:11.48000:38:11.490 the heat transfer surface and heat 00:38:13.82000:38:13.830 transfer coefficient and along with the 00:38:16.61000:38:16.620 enhancement in the heat transfer surface 00:38:19.10000:38:19.110 area we get enhancement in the heat 00:38:21.89000:38:21.900 transfer coefficient so this is a way we 00:38:27.35000:38:27.360 fin along with that we have a perforated 00:38:32.09000:38:32.100 plane perforated heat exchanger so in 00:38:35.15000:38:35.160 the rectangular it is not shown here in 00:38:37.88000:38:37.890 the rectangular plane rectangular fin if 00:38:40.67000:38:40.680 we have you know perforation on this 00:38:44.84000:38:44.850 surface on this surface at regular 00:38:47.27000:38:47.280 interval if we make perforations so then 00:38:50.27000:38:50.280 we find that it is also a kind of 00:38:53.24000:38:53.250 interrupted fin so the fluid will come 00:38:55.58000:38:55.590 here and it will have a passage or it is 00:38:59.99000:39:00.000 or this flow will try to go inside or 00:39:02.84000:39:02.850 that flow it fluid will try to come out 00:39:05.84000:39:05.850 of that perforation so thereby giving a 00:39:09.83000:39:09.840 breakage in the boundary layer that also 00:39:12.80000:39:12.810 we often use in plate fin type Felix 00:39:16.67000:39:16.680 Mears thank you thank you for your 00:39:19.91000:39:19.920 attention
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Engineering company LOTUS®
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