Tubular Heat Exchanger: Shell and Tube
Welcome to this lecture on tubular heat exchangers. And todaywe will be talking about the shell and tube heat exchangers in detail. But before going to that in details we will first solve that incomplete numerical problem that we have takenand we have opened and we have also calculated the external heat transfer coefficient using the appropriate correlations and we have obtained a time and date you so we had gotten h I s 4911 watt per metre squared kill me and we have obtained 13451 per metre square ASDA heat transfer coefficient of the annular space so based on this data we will be able to calculate the overall heat transfer coefficient that is equals to one by you is equals to 1 by this is in terms of the external diameter and this is did you know by t.i. by Asia plus this is 30 and then Ellen 30 by t.i. so where we are taking Carol of the resistance of the wall and this is the thermal conductivity part of it and then we have one by 80 this is the heat transfer registers offered by the external I am in the annual afraid this is the resistance offered by the fluid and in the metallic park and this is the heat transfer over by the internal This is how we calculate the overall heat transfer coefficient and then come out to 9:48 metre square to calculatewe do not know what does log mean temperature difference rego park only be able to find out the area already and 948 and 15 and 2 calculate the area of a so this will be about 1.25 that’s the hideous once and once only we know that this will be able to calculate will give you the number snack we’ll all sit to the next the discussion that we are talking about the shell and tube heat exchangers and you have already learnt about it in the earlier classes now will try to go in details about this selling tube heaters so we know it is the one of the most versatile type of sedation is used in the process industries are given in the nuclear plants and they can be used as as appreciate is water heaters then you know condenser and it also Bluetooth use data cable wireless and they can also find applications including a bunch of animal in the ocean in the medical applications particularly whenever we're using heat exchangers where it meets occasional still coming so that gives usabout that and the advantage lies the not only with the design flexibility it also gives us pretty good opportunity to use some of the fluid strange that the pressure are very high and as I told you that in the cleaning options is again another big advantage of this particular type of collection list whenever you need whenever we are using some dirty clothes and which often generates scales on the heat transfer services and thereby it give some kind of following resistances to the a transfer we have to often clean the exchanges and that it’s not possible for many it’s not possible with many exchanges to regularly really particularly when thedelete all of the extra small but in case of shell and tube heat exchangers it it gets that opportunity to clean it at regular basis but again it is so versatile that any kind of heat exchanger design I mean we have a guideline given by the two bullet exchange your manufacturer association and that is in short-form mein Kala tenor and they tell you exactly what are the standards that it to fulfil design of the heat exchanger so we have taken up the heat transfer coefficient for the hillside at in in some of our earlier at the classes are in earlier lectures and dad might have told you how to evaluate the heat transfer coefficient but as you can understand from the latest same details of this class is that that is an oversimplification of the actual process but in reality will find that the processes are much more complicated so we will look into the crystal ball and the design of the heat exchangers how it looks like for example the there are different type of shell and tube heat exchangers as we have told and there are we will only show some of them in this here you can see all this is the cell site through it so the fluid will come like this then it will be flowing on top of the fridge or out of The cubes and then again it will come like this it will come like this and then finally it will have a exit from this ain’t so here we have the battles so these buttons will allow or brother do not allow the continuous flow of the freight along the tube lamp so it will make the floor I like following this particular subject or like this and it will finally come out on the other hand we have the same side throughout the two separate which may enter from here and then then what will happen this way will enter over here getting distributed coming over here and find them one and then but this is a single cell fast so this is single cell put your past heat exchanger and Hilda and other speciality is that of this particular type of action yet is that the this is the new shitt this is where we have the team sheet and this tube sheet is drilled with the holes to best fix the that’s why this is fixed tube heat exchanger with 22 passes so it has obviously gives an advantage in the sense that whenever we remove this part this to end if we remove if we onboard this parthere in this case what we find is that this is again the shell side to fluid that is no problem it will winter and depending on the number of depending on the number of these battles are the type of battleship will be time for retired and finally come out of it but what's about the tubes tied to it this is coming over here they will get and come out of it from here this is double pass so that’s up to that part which way this complication we have in the design of the section yet so now you can understand that then maybe situation where the inside and the shell size fluids are off pretty different temperature and that measures are some kind of sandwich generation so thermal stress will be generated means the sale and the cube if they’re getting along get it at a different rate then it will generate some kind of thermal stress so that means we have to allow the teams to expand I mean if such situations after then that’s tubes will be able to expand as contract a contrast to the shelter so this allows this particular type of exchanger design allows expansion of the tubes how it looks likecommon type but this is this is what we call as in the YouTube removable handle this is one of the simplest geometry that is possible safe here the same cycloid as usual you can see that depending on that depending on the back bills this week will be entering here and it will come out from this I know about the about the site fluid it’s simple it will enter over here and this is just like that they will come out and move out of this place the advantage of this month is that the expansion or differential expansion of the tube it is automatically taken into account it’s already are you build and that if it is differentially expanding it has the possibility to expand it on this site then only is good enough to accommodate all the I’m going inside the cube we are not in a position to clean it so that's the disadvantage with otherwise you will find back this the standard shell and type of the front and it types and is already specified as I have told that the tubular exchanger manufacturers association or Taylor has given so many standards and that according to that standard we have a different type of front stationery sets and then we have this is here stationery heads and the share time so as we have seen in the previous I’m in previous lives that we have one entry side one exit side or the left side and then we have the different type of cell sites to visit different it is a start the specification of the standards we cannotany type of cell for example if you look at this is and this is one person that means this will come here and move out like this this is a too fast so it will come like this and it will be coming like this here this is a speak to split floor and there is coming inside getting distributed and then rejoining and coming out like that so similarly have double speed do we have the divided floor we have the kettle type and we have the crossblue so instead of leaving them by individually double-speed floor are divided floor we use these numbers hjk like that x this is the type of the shells future in his similarly as we have seeing that we have the channel and recoverable cover removable so this is for the entry and you said this is named as a similarly we have all the configurations like a b c and d and on the side lmnp like that we have different type of configuration specified by the table so while designing the heater is using a particular type of while solving a particular type of exchanges we had to look for this defined style of nomenclature that has been given by them suggested by Tim Tim so now if we look into the different type of that sells we have several type of vehicles that is possible so the buttons are basically providing are giving to type of advantages one is the first Apollo the Egyptian the mechanical stability to the tubes that means that if a long tube is there sorry if long tube is there and there is no support for that one that is a possibility that you will be having a sagging and the middle or at the at different points so that gives us some kind of mechanical support to this and not only that it also allows longer type what’s the fluid from one to the other mint and thereby enhance is theresponding to this the other one response to that we have about 30 to 35 percent or percentage of the discount and that card portion is if it is on this side the other one in the next immediate successor one will be on the opposite end of it that’s all this is the single segment that police used by the same case of does a segment as you can understand that we have this part 41 and and the other partCrystal palace is one pint and then we have this time and then we have this part and design doesn’t come here this was come here till like that their identity sequence and then wewe have this is on the site include is obviously going through this as usual I’m sorry this phone is typing this is that you paid for it this is the same side fluid and we had this is the baffle this is the battle and battle between the bathroom and that you we have a small gap tooth which may allow the sell-side fluid to pass through so that is what is is a shared this is the it is forming a kind of orifice and between the muscle and the cube and that’s why I even the phrase will be passing through obviously you can understand that it will give you a very large I mean kind of heat transfer he transferred but at the same time there will be large amount of pressurebut I understand from the geometry of this particular that that you know of any kind of the more design will be I’m in quite complicated if we have to really look into it such a battery so here is the way we know the heat exchanger and in a basic design approach what we could do is try to calculate of the try to pass the estimate a kind of design all the heat exchanger and then we go for the rating that means we know first of all we have been given the inlet condition of the freight and we know the book The twits streamswhat it is not known is the overall length of the exchanges and other details how many tubes how many number of tubes or what is the time you tell what is the cell diameter etc etc so what you trying to do we make a rough estimate of the overall length and the harrisburg area when we make an estimate of this feature is the surface area and then we’ll try to figure out the actual number of The cubes in TV with the number of teams we will be trying to find out and from there when we have some kind of geometry known to us then we go for the rating problem as if we have finalized the heat exchanger and we have the inlet temperature known to us and then we’ll try to help late the exact temperature to basically it is the kind of trial-and-error methodshow me to be .9 or around because any counter-current exchange is it is one but it’s not really a counter-current exchange it and actual value of the f finally when we go for the rating problem we have to get the valley and this is 0 now we have to make an estimate so we had a certain known value it is already also given in this particular book one can refer to this book file design in such an affectionate and from there we get the value of you and from there we can try to estimate the age she wrote once we know the issue we try to find out the number of cubes in terms of the spiders and Lantus already know and then for 2:01 we have this iswe will talk about this particular type of constant why it is coming like this and finally we have this relations by which we can try to estimate the number of tubes for different number of passes and we have this year equals to 14 90 degree and this is for 45 degree that is the cube arrangement this depends on the type of temperaments where’s the following if it is like the way I’m in there 40 Avenue there at 19 at all in line configuration then it becomes one if it is 45 degree then this is also this is alsowas for 30 and 60 degree angle if it is 30 degrees it is 0.87 and if it is 60 degree also it is CL comes after which point 87 and that .9 and .93 and .85 all this newfound strength calculation count count count calculation constant that we have I mean used in the area I’m in relation in the previous in the previous flight if you look at we have used that relation and based on that we would be able to calculate the diameter of the cell site so we will try to look at designing a little bit later on. And finally once we have this known to us, then we can go for it. That’s all, thank you.
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