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[Jaimin Patel_1588]

freinds i m fianl year student of mechanical engg.


i want to design shell and tube heat exchanger for following problem:

exhaust gas is coming out at 230c
i want ti use this exhaust gas to heat water which is intailly at 30c
i want to make it up to 90c for other uses.

properties of gas are as follow:-

Mass flow rate						=2.11kg/sec
Entering Temperature		   =230°c
Specific Heat Capacity		   =1109.29 J/kg-°c
Viscosity Of Exhaust steam   =8cp
Thermal Conductivity			 =0.5623 w/m-k
Density									  =0.8 kg/m³

properties of water are as follow:-

Mass flow rate						=1.21 kg/sec
Entering Temperature		   =30°c
Leaving Temperature			 =90°c
Specific Heat Capacity		   =4186 J/kg-°c
Viscosity Of Exhaust steam   =0.0007  kg/msec
Thermal Conductivity			 =0.619 w/m-°c
Density									  =995.6 kg/m³[/b]
[b]

i want ot design for AES type heat exchange plzzzz
help me for this


and give me detail drwaing of AES type heatexchanger

[Art Montemayor]

Jaimin Patel_1588:

I assume you have been given this assignment by your instructor(s). Am I correct? If so, then the basis for the problem seems to be out of the normal, practical way these type of problems are met in real life.

The basis of the problem is that you have a hot, exhaust gas at 230 oC and you want to use it to heat up cold water for use elsewhere. That’s fine, except that you give us BOTH the exhaust mass flow rate and the cold water mass flow rate. That is not the usual, practical, real-life, situation. You either are given the exhaust gas flow rate OR the flow rate of the water you need to heat. It is then your calculations that determine the other flow rate. But that’s OK. You employ the same heat balance equations to find out the terminal temperature of the exhaust gas. However, it is good you identify yourself as a mechanical engineering student because normally you would not be exposed to phase phenomena or equilibria and what you are confronting when you cool down an exhaust combustion gas (what I suspect this is – in spite of you not identifying it) is that you can condense out part of the water moisture in it and any other soluble components – such as SO₂ and SO₃. When you do that, the condensate that drops out of the exhaust gas forms an acid solution and corrodes everything it comes in contact with – including your heat exchanger. Therefore, identify exactly and specifically what your exhaust gas is - just as you have specified that your other medium is pure water.

There are perhaps hundreds of prior threads in our SEARCH machine that address the design and calculation of heat exchangers such as this one – including the equations and algorithms to be followed and applied. I have personally uploaded many Excel workbooks that give complete illustrations and sketches of TEMA heat exchanger types. Have you used our SEARCH machine to find this information? You should exploit this source of information that has been generated and made available specially for you and other students.

Have you obtained and studied the classic text book, “Process Heat Transfer”, by Donald Q. Kern, McGraw-Hill, published 1950? This book contains excellent and specific example calculations of this very same topic. You should make every effort to get access to this type of engineering information if your instructors have proven to be short-coming in guiding you to methods and instructions on how to proceed with a manual calculation of this type of heat transfer.

I hope these recommendations help you out. If you have done any work towards solving this problem, upload it in an Excel Spreadsheet and our members will surely check out your detailed calculations and help you out in your work effort. However, we will not do your homework for you.