Analysis of Fin Plates in Fin Tube Heat Exchangers – Part 2
If you recall we were discussing fin tube heat exchangers. So we were actually preparing ourselves with the analysis which will help us to design a fin tube heat exchanger. If there is a need, now for that what we want to do or what we need to do is do certain estimations estimation of area it cetera particularly in defence and that is what has been done in our previously we will continue with the results of the previouslythat will be given by aal technique that is actually in the inside and he is the heat transfer coefficient and this is one of the one of the game to determine height from the analysis we have not done yetthe temperature in equal to that of the cube this is how we can get our stuff this week because that is not participating participating in the idea ofthis is the bare area this is having the temperature of the beer too so we will take it as it is this is how in the not sell it will be about 4 will probably know it but as this is important so we can again repeated it so let us go to the next life the effect of heat transfer coefficient for the total surface taking into account of the Philippine CNC is then each bar that is equal to ETA is 1/8 + a / a into HR some factory fgk cities lives we never finish there we are getting more surface area for a transfer more surface area we are getting for a transfer but unfortunately the temperature temperature difference for the transfer that had is that it is along the link epiphany along if it is so either we can take care of it but it is always easy to being with constant dull cutting we will not consider variable delta-t along the surface of the field we will consider only a constant getting along the surface of the sea so if we had to do this then what we have to do we have to x factor or heat transfer coefficient x in both cases these factors are listed so this is what we have already define definitely CNC we have define the overall service efficiency so basically we use the maximum temperature difference but the maximum temperature difference is not available to the entire surface to the surface area is reduced by multiplying it with the factor which is less than 1 so this is what your family can do that we can think of that heat transfer coefficient for the entire surface is not equal and that heat transfer coefficient we are we are multiplying it with the factor called as effective in transportation and y is equal to b is a adult or a bar concept ofblueprint you actually I had told that there are two types of feeds on the outer surface of the youth loafing do that is the fi height is small and in this case what we do the average convective heat transfer coefficient may be calculated from a correlation in all the cases we will useif you are I think you will use and the number of I am not going to burden you with the coalition they are available from where is application only for the sake of completeness this correlation average convective heat transfer coefficient calculated from a correlation of average muscle number of the whole team the original number is denoted by a new bar as a function of Reynolds number and geometry Reynolds number how are we going to calculate one thing you have to understand that the thing to create message for rear floor which is not constant throughout throughout the field you the area of air flow paths cross sectional area of the Earth is not fixed so what we do we generally use to area 1 is frontal area of the heat exchanger sometimes it is called fasir and he also use the minimum area available for the year the minimum area available for the air or gas to flow that gives us the maximum velocity as we are considering steady-state operation of the heat exchangers so min area will correspond to maximum velocity also we will do this let’s say we have got mass flow rate of gas is in the max maximum velocity we can calculate divided / s mean in 20 ruins intensity of this week this week is meaning the minimum cross-sectional area which we have already calculated in our previous lecture we have shown how to calculate is mean I will again asking to refer it back and calculate his me or get the expression of is mean by your phone by your own calculation by your own television show please arrive Reynolds number according toThis is how we Will calculate the numbers number everything number will come from average transfer coefficient the characteristic length that is the outer diameter of the tube outer diameter of the field through which we have also used for the calculation of Reynolds number and then we will use the conductivity of the showing fluid that is here for any other gas today’s things simple only thing is that we have to be careful what characteristic linked yet taking what characteristic the lost city should I hope you the recommendation is something like this number is equal to .75 to the power point 361 by DT to the power 106 in by 84.11 to the power point 36 and then there are three factors correction factors if one if so what are their nursing number will be a function of Reynolds number and dial number 620 dimensional numbers are there this is not kind of the simplehuman soap medical parameters this geometrical parameter what is the length or height of the spacing between the field that will be that will be and diameter of the fee that is also also all these things and then we're or eveningactually in heat exchanger there maybe heat transfer in between the solid surface and we are the gases between the solid surface and the floor balcony fluid and the solid surface we have different temperature difference in temperature may give rise to property valuation and that property valuation has to be taken care of it and takes care of the property because the bulk fluid temperature and the solid wall temperature dew point temperature number of how many are generally more that you brought it to we come closer and 83 factor for many different are close to give me the score betweenShabbir be the middle number calculated at Balfour temperature prw that is trending number calculated at what temperature do the powerpoint to 1800 w is based on the mean surface temperature be to is equal toit cannot be done one goal without taking the help of a heater is particularly because and then only we calculate thebed factory to text via count of the number of you both approaches unity for large number of rows and it takes into account the electrical element of leafy unity4 common kind of 21 this latest go to Hindi transfer north beach at Long Beach the one is called transverse which which is normal to the direction of flow and p2 is there is in the direction of flow it is called see it is called the location is important and then if one is number and then and then we can have different coalition also they are availablesecond correlation see that it is based on Reynolds number and friends and whenever house number 100 to the power n then probably it will be x some sort of a function of view some sort of correctionbut whatever we have done from there we can see that muscle number is Indian rail in by just kind of a constant re to the 41 and feared to the poverty to c1 and c2 are a constant then if it is a complex geometry then some metrical parameter will come that means there are more links which are important one can have the one select one characteristic length but other lanes are also important so then wanted to have some dinner and then correct temperature forsince I have said hi thank you for helping to transfer obviously the correlation at the job is more complex they could listen at the bottom is not that complex but there is one tell which leads is the total area of the field and all of that means for the future is there and I think you very sure he is calculating all this and it is supposedremember we have got the idea of being with you so that is important in certain cases that will be needed for calculating think this is one example basically what we discussed we have discussed how the number is to be calculated for roofing to be transferred and I’ve been showing all the definition of number is that is this definition we have this definition we have used organic conductivity this gives us support from the external surface of a paint you we like to calculate what is the transportation sorry what is the date of the transfer we can do this analysis we can also do this analysis are we can also in this analysis in the sixties to be designed and we have to calculate the overall heat transfer coefficient because in that case the gas side which bar you need to go and get it but you have to get sage park from this is dependent on gas side area or Field area that's why the previous lecture mijas Spain because we have shown you how to calculate the same side that is obviously but that's correlation week working in boobs will requirenext what we we take up as I have told that due to the complex geometry of the field we had to have these complications and calculation requirement of calculation similarly for pressure drop calculation also these inside is big unique compared to its next to see how to pressure drop calculation for defence now let me tell you one word of caution I have taken up some example but there could be other examples and there could be other correlation particularly their many medications and geometry can hurry to a very great extent that we can have played so we can have serpentine kind of you we can have different kind of you play out excetera so what has to be one has to take one has to take some sort of judicial judicial action while selecting the coalition’s and while calculating the geometrical parameters okay so what it is but it is not suitable for this is what you want to keep it goI am leaving Sanford Avenue we have told that okay the radial feel that their calculation of the efficiency of radial winning all their function true what you do we do not calculator function chart or graph from the graph determine if if I could have you pick up a little bit early AMC drrd by Dr close to one will find that it is becoming and basically then we have not do we have got two ways now either we can use the chart for the efficiency of radial fee or we can use this kind of formula and the formula this is quite handy to eat with this I come to an end so we have learnt quite a few things that we have learnt how to take how to do the calculation for the inside of the humidity calculation and how to estimate the heat transfer coefficient and then again I have told you and easier way to calculate GPA calculator thank you and then we will proceed with our discussion where we will do the pressure drop calculation for the fin side.
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