Analysis of Fin Plates of Fin Tube Heat Exchangers
 
Welcome back so we’re discussing heat exchangers and a very important type of heat exchangers that is fin tube heat exchangers, is the topic on which we are spending some time. As I have told that tubular structure is very common in industry and stimulus structure is very common for you text ads and with tubular structure we can have different type of it is been just like you will do what the fight is exterior sealant tube heat exchanger should double pipe heat exchanger and said on Twitter exchanges primarily there for me quickly quick application what does it mean that means that two fluids both of them will be in the both of them will be liquid or liquid phase to the Central tube one liquid will pass through the sale of the animal passage other liquid fast but there isthat if we can have liquid through the tubes and outside the tube we will have gas and gas heat transfer coefficient is small so we have to have some augmentation for the gas for the gas side we can have framed structure on the outside of the team and for a circular tube or for that matter you got any kind of geometry we can have three types of these things could be along the axis of the cube number of scenes so that is called longitudinal fee and already we have seen the analysis of longitudinal fissure form of these realities at different intervals different axial interval this lady LP can be provided on outside of the radial think we know how to analyse but there could be another variation of pink youth exchange which we have mentioned and again I am mentioning because that is important that there could be integral tu sree TLC plate which will be pierced by a number of so that way we increase the compactness of negative if we go to the next slide in the next like what we can see different designs of plate in heat exchanger where the fluid is parsingso basically black things have been used but we should have mentioned that you knew was also there so playful and you type of heat exchangers so you can see the tubes I did not show me it is clear to everybody for the tubes and here we have got plate features of plain plate fee and here we have got basically what is important to note here that tubes are having different kind of punishment in this the tubes are in a particular element which is called plane inline element in this this plate is plane so it is called plane and then it is staggered show you see this is a staggering me in the first row we have got 32 in the second row the third tubes are slightly shifted from the position of the fastest route to their struggle and in the second case we have got again will be in client that is see and we have got this tablet so you can be arranged in line arrangement and staggered element please can helping plates can can have different kind of geometry play new military and wavy geometry has been shown there could be several other kind of show with these letters go to the next flight to hear I have noted the very important points p&q with exchanges are often designed to have pink lips pierced by a number of cubes several complex at Eddie’s parallel to each other so this is what we will be able to see here the plates that are parallel to each otherthe mother coming to this is kind of a passage this is another kind of a person who is wavy and this is plane passes something like that we will get if we go back then several complaints I don't parallel to each other to neighbouring thin plates constitute the passage for gas block convective heat transfer from the paint place needs to be determined but what is the temperature variation of the conflict between plates will have different temperature at different point near the temperature supposed to be at higher temperatures andso convective heat transfer these two dimensional or other ticket distribution is two-dimensional so accordingly the convective heat transfer will be affected plates are basically two dimensional beings and we have done so far only one dimensional analysis analysis of two-dimensional things that difficult for the design of heat exchanger approximate one-dimensional calculation is adopted this is what I am going to talk about inspector the crux of the today’s discussion is this insect dimensional figure see how to design them withwhatever knowledge we are having we are having the knowledge of analysing one-dimensional team so we we try to hang out the back with some predicting modification do you think you and I have already shown and discussedgoogle.com in line and two very common cases are in line and staggered array of views as shown in the figure store previous figure it has been shown in the figure after this we will ensure this part of the field play affected by heat transfer from a particular that you are shown by Red line so if it is a two-dimensional feel then you will have the transfer by conduction or from the tube with thermal energy will spray in the feeling by conduction and this will be restricted within its own should that John is shown by the client as we will see the diagram it will clear depending on the tube arrangement it should be a regular or irregular polygon depending how we are eating with you there two different kinds of polygon starting from Square rectangle et cetera and they could be likeyour regular design calculation what we do that we have got one-dimensional scene analysis already available we want to adopt that but it is a two-dimensional feel so we have to modify our analysis shows this modification is done by two different method one is equivalent and ulysse method and another is sick with this background latest go back to the ferry crossing to the next slide equivalentso basically we have got a polygon okay so that polygon can be replaced by an equivalent circuit what is meant by 2000 circle the area of the polygon and the area of the cube outer radius if thereinstead of polygon now we’re getting an annular cumetri which is having inner radius is equal to r and outer radius is equal to ask eri and Ali alone then it can be determined by the usual method for obtaining the efficiency of a succulent how to determine the circular we do not like to use those bessel function so basically there will be some sort of course our chats so from there we can do it now with the advent of computing power probably one can have some sort of software for calculating the phanaticmc and there may be a better method which will be slightly but so far what I can suggest that the Philippines available and other parameters which is already have define deter andok so we are getting out here getting is a quantity which is already specified and then we can proceed play Casey the diagram herewhat will happen surrounding area of the few in the field that will be affected by the by the temperature of the periphery of the cube and the area is shown by Australia show the effect of the tube will not penetrate in the field beyond the red line so what we can say that if there are large number of teams which will be there in a bit so all the tubes we’ll have some sort of the square and the grade boundaries are also had Molly insulating boundaries or a diabetic wound so there will not be any transfer across the or normal to delay found that is so what we can see that our team played which was really bit complex to analyse now represents a situation where there are number of circular tube with square kind of a square kind of iffy and the square thing has got different lines of symmetry so they said in June that is one smallest ocean of the sea which can be repeated to get the Arcadia from the symmetry of the problem fromthis is how we can get the funeral in line at it Monday is defined by two pages one is longitudinal PPL and another is transverse ppt depending on the process requirement we can have different values of pl and PD the particular case has been shown for SPL and TT are the same should basically we are having an inline Square array of news Hindi film tickets so let’s go to the next slide so here I am showing the struggle so you see this is the lineup to the next line of view is little bit simple lines of The cubes and little bit so this is a salad thisone piece define the humidity that is what is p and of course the diameter of the tube that is important these I can define deviant sostaga the area generally what happens let me tell you that why there are two types of element has been seen that staggered array generally gives more compactness and more heat transfer could be there the fluids cream which will pass this few behind The croods train which will pass the tubes let’s say this is the air flow which is taking place okay and flow of liquid isthis is not directly coming out on the next you it is I mean it’s okay to be fairly on the other tube show where the boat takes a little bit died down so we will have a good mixture of kind of good mixture when we are having Turkey in line this is something like this let me draw years so go take some for me hear good except for something like this so big is falling here here here so you can get better mixing and a better compactness bakery heat transfer and compactness in the case of struggle and that's why we have got in line and we'll be having this kind of thewhat we will do we have some sort of the circle whose area is equal to the area of the hexagon probably in the drawing it is not that accurate but this actually really green circle area and the Wrexham area there we will assume that this central cube is surrounded by a circular field is given by this is what ok so for that I will explain it I will explain it once again with the help of diagram let me go back to the previous slide some previous slide and then we will have a so what we can see that so many tubes are there then in this case case each tube we can assume that in the first case which tube is surrounded by Square kind of and in this case which tube is surrounded by this is what we are going to that is the first first and second what we do here with these qualities or rectangle or regular or irregular hexagon we convert them into our life is very simple we know how to determine the efficiency of circular and we can process it so that is what we’re going to do and then equivalent annulus method I have already and I videos of the spin cycle cycle and from there we can determine definition we have gotthat will also you will see from the diagram efficiency of a radial field with these two radii calculating efficiency of the Hyatt sector is it high and it’s area is AI then the efficiency of the polygon dolphin bisector method is given by this particular formula demonstration of this is our second let's say this is the outer diameter of the tube which is given by the outer diameter is given by d and the radius is given by our eye and then this is the sixth this sector if it’s to give me the polygon is so what I am doing I am dividing this sector sorry dividing this symmetric part of the team into different angle assist this is one angle of sector II the cistern and then it is angular sector I amI’m here alone and from this car is known so it is known for doing what I and II I can get the efficiency is different for different angle of sector which I have done so I will have different efficiency and these sectors angular sectors are also having different area so combining the area and the efficiency formula which I had with that I can buy off of the polygon so obviously obviouslywhich can be obtained by vedic mathematics how to determine definition of a circular I mean attached to the outer surface ofwe are at mine in approximately it’s at CMC from this is what we had we tried to discuss today if you have got any confusion or querry come back to the forum and we will try to address that. So with this I like to end today's lecture.