Chemical Engineering - Heat Transfer - Discussion
Discussion Forum : Heat Transfer - Section 1 (Q.No. 12)
12.
In the equation Q = UAΔt; Δt is
Discussion:
9 comments Page 1 of 1.
Vivek Kumar said:
1 decade ago
As the temperature does not remain constant in input & output stream of heat exchanger ie it varies, so logarithmic mean temperature difference (LMTD) is taken. But if LMTD<2, then arithmetic mean temperature difference is considered for heat transfer calculations.
Pritesh patel said:
9 years ago
I think it will D option prefer in their questions. Q = UA Delta tlm where Delta tlm is the log mean temperature difference .
But in question Q=UAt. Where Delta t used for the difference of average bulk temperatures of hot and cold fluids.
But in question Q=UAt. Where Delta t used for the difference of average bulk temperatures of hot and cold fluids.
Aashi said:
8 years ago
Yes, I also feel that option D is the right answer.
Ritik gupta said:
7 years ago
For cylindrical shape, we take only log mean temperature difference.
Deena Nath Tiwari said:
5 years ago
D is the correct answer.
Rakesh Choudhary said:
5 years ago
For counterflow heat exchanger ΔT1 =ΔT2 possible in this case LMTD Become 0/0. So for all condition D is the correct answer. And also LMTD we use because of the variable in temperature difference between the two fluids.
Dipak Gund said:
5 years ago
C is correct answer because focus on the you symbol it is a overall heat transfer coefficient so in overall we take LMTD.
(2)
Ankit saini said:
4 years ago
Thanks @Dipak Gund.
Magan said:
4 years ago
Thanks @Dipak Gand.
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