Fin Heat Exchangers | Plate Fin Heat Exchangers - Part 2 | Alison
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Module 1: Fin Heat Exchangers

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Plate Fin Heat Exchangers - Part 2

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Plate Fin Heat Exchangers - Part 2
 
Welcome to this lecture as we will continue with the fin types we are talking about the plate fin heat exchangers geometrics and we have shown you the different type of fin geometry possible. We have talked about the plate fin are, plain rectangular-fin we have talked about the trapezoidal field we also talked about the offset stripping where we found that it is giving extinguisher transfer surface area not only that it is giving also audit assignment simultaneously trying to extend or enhance the heat transfer coefficient and then we had talked about the way we feel when we found that it is the continuous pain but at the same time the geometry of it is such that it is giving vacancy in thethe other one the other one is the way we finishing can understand from the geometry of this is the cemetery of the fin this is the third passage and we have this floor taking place in this when the fluid flow is taking place they will find at that point there is a separated boundary layer is getting separated at this point all at this point and there are pics and this region and again it will joined the attachment point at this and in this case where we had the offset stripping the floor is taking place and the floor having is getting the laptop with this part and there is a French generation of the band really hard at this point and this point in every regular interval as I told you that this is the length length called l lens length we have at regular intervals there is a generation of this or breakage of this boundary layer and as a result we find that this boundary layer is regularly getting interrupted at these locations resulting in enhancement to the a transfer at the cost of some facial drop penalty ok so in this month the pressure drop penalty is bit less as compared to this side but we have I mean particularly when we go for the very high transfer that we look for this officer truthful and this is in regular use in different kind of a place in Tyler Texas so again this is the plain rectangular feel how it looks like as you can understand that there are several parameters of the plate field types where we will find that this is the frame height for example this full height the screen height can be varied similarly the thickness of the feel you can understand that this if someone is making a feel of a with a 3-0 run or thick album at the same time the same frequency I’m in the number of fans per unit metre or parents sometime we call it feel frequency or the number of Trainspotting show number of fence per metre so that’s another parameter that will tell what is the kind of passage in passage is mija so 2050typical language recall for this type of face and in thickness as you can understand that these are the type of I mean parameters we look for all we have the options particularly a designer will have options to choose from the different high-top feels different when frequency difference in thickness and that will change in the you transfer coefficient for different type of things so this is the plain rectangular thing and then we go for the next one here we can see this as a sedative pain or upset stupid here I am in this offset stripping is also called a sedative so did it feel or offset stripping it is often called and this often we go for as you can understand that this floor is coming here getting divided and then a party is taking a flowing through this one then other party is continuing in this passage so this is the regular floor passage sometimes or generally when it happens that the floor can take place on this direction also this is called the hard way configuration because the hardware configuration and so but generally I know this is not the obviously you can understand that the friction factor all the friction will be much higher in this configuration is v share this is an interactive thing as you can understand that the field is the film passengers like this very nice gifts open her things and that type of thing very similar to this one it is called that carry morphine this is sometimes the idiot if the geometry is not it is a very fun time so now we have another this is another thing that is called the low fat face so here’s what we have a certain interval of time if it is a rectangle is your battery or say if it is kind of truck is like a tree then it have after certain interval of time you have this kind of opening and similarly this double angle will change after certain time so if it is on this direction then it is on this direction so that means of it this way and that way but but the way the fruit can flow through so if we look at it on this direction is so there will be this kind of floor passages that will be this kind of floor passages I'm inthis is called the local train so this is also isn’t regularly used in different type of black Pink lyrics in that your mattress stopin case of bronze floor tile place in heat exchanger easily it is easy to understand that we have discussed in the last class that we have two channels through which one fluid is flowing in this direction and the other fluid is flowing in this direction so this plate is flowing in this direction and destroyed is playing in this direction so they are at rectangle at an angle 90-degree to each other and is geometry is easier to conceal and it is easy also easy to fabricate just to be hard to arrange the sideboards and the separating plates and the fence one over the other in a check and then you have to assemble them and you have to get dressed so that gives you the heat exchanger matrix of the core of the heat exchanger but is it that we always go for the cross flow type of heat exchanger in Franklin type of protection just the answer is I guess we know we don’t go for always go for the plate I mean crossword type of it is near the counter current are the parallel flow heat exchanger or trans counter current of heat exchanger all different geometric whatever it isif you hear the sidebar on this side and this is the primary interest for surface area and this is the friend and this is the end plates so but two plates and the two extreme and at the end plates so this is a new plate at 1 and there is another and played at another end this is sometimes called in place or it is called the couplet so in between we have the different layers so this is a clear one we have some type of thing and then we have another related say maybe you know it is a triangle offence then we have another save this one then we have this rectangle one and then we have the way we feel no it is not impossible configuration it will not look like this I will this corresponding layer will be like this and that will be similar and shared this is blocked so you cannot see anything from this end so like that if we had this arrangement this is easy to construct as a website but at the same time we can also go for the other construction will come to that part so so here we have the head is this is the head so the fluid is coming to the header it is getting collected and then it is going to the individual channel designated for the fluid to all the flavour so this is the header 481 and this is the head of this is the head of fluid to this is the incoming fluid this is the exit for 8 and again in of the phrase will be collected in the saddle and then this way to will come out similarly all the fluid with first accumulated in the head then it will be getting distributed to the Independence channel then finally they will be collected in the outlet head and then it’ll move out so that’s all this process flow heat exchanger plates in prosper it in gear looks like quickly look into the design of the counter flow heat exchanger understand that both the fluids had to enter fromthere is a kind of distributed so hear the fluid is entering from this and this is a perfect number one number one is entering from this and it is coming over here and as you can understand this is getting distributed and coming like this and then it is coming like this and coming out finally this way so what we have if we take out this one like this we will find that we have this path then this geometry it’s this is the distributor we have different kind of distributors and then it is getting like this and then again it will be collected finally and then it will be coming like this this will be this and then we have this kind of distribution on this sideso the very next year but people find is that I will believe this is how it entered and how it has come out this is one direction the next 28 the 32 it is entering in the next level so in the next level they will find that this fluid is entering this is entering from this and this was designated for the first one this is for the second one and it will enter like that and again it will find some kind of distribution there and then again it will be channelized like this and it will be sunrise like this so between these two regions you will find that there are these two fluid fluid one and fit two are flowing other parallel or accountable to each other so that’s what is the counter flow and went and we have the distributor fence and the entry and exit and we need to carefully designed that distributor for this contact Allen theaters near so when it is a two-step counter-current heat exchange we have this kind of distributor there are different type of distributors so here comes the sun view of the distributor here you can see that this is the kind of and it will come out from this land so this is the direction of the flow this is where it will enter this will follow this path then it will come out from this and what’s the weather this one just on top of it if you put this one it will come over here this will come over here this will follow this path and then it will come out and this is finally coming out on this side so if we just superimpose on top up this these two layers if we put one top of the other Sophia even find that one so it is entering from this and the other traders entering from designed so but they’re not mixing with each other but they are constructing a kind of the slate flooring in this direction this place is also in this direction services constituting a kind of parallel stream it is in there but instead if we say that one fluid is flowing in this direction and moving out on this direction and if we allow another plate to enter farm these daysof this kind of Life antibiotics and yes we’ll talk about this and details about how do I determine which affected and effected this cold wind chill factor in x factor this is particularly for a very faint of 10.2 hide then we spell the way we think 18 is the fence paling 10.15 2mm is the thickness of the thing and we have different kind of the affected and pressure drop English and for the Plainfield weather Plainfield so this is the kind I mean for each thing we will have a different kind of characteristics line in the heat transfer and pressure drop and we have to look into this kind of pressure drop and heat transfer correlations for these fins before we take out the heat transfer analysis. Rhank you, thank you for your attention.




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