Log mean TD
Log mean TD
(OP)
Hallo to everybody
Please, I would be grateful if someone of you could help me in following issue:
I am dealing with this issue, that it can be apparently simple, but I cannot find any reference about it.
In an heat exchanger, when defining logarithmic mean temperature,
Th1 = inlet temperature hot fluid
Th2 = outlet temperature hot fluid
Tc1 = inlet temperature cold fluid
Tc2 = outlet temperature hot fluid
In case of coutercurrent flow configuration
Lmtd = ((Th1 – Tc2) – (Th2 – Tc1))/log((Th1-Tc2)/ (Th2 – Tc1))
While in case of parallel flow configuration
Lmtd = ((Th1 – Tc1) – (Th2 – Tc2))/log((Th1-Tc1)/ (Th2 – Tc2))
Please, does anybody of you know which is the expression in case of cross-flow configuration?
Thanks in advance
Please, I would be grateful if someone of you could help me in following issue:
I am dealing with this issue, that it can be apparently simple, but I cannot find any reference about it.
In an heat exchanger, when defining logarithmic mean temperature,
Th1 = inlet temperature hot fluid
Th2 = outlet temperature hot fluid
Tc1 = inlet temperature cold fluid
Tc2 = outlet temperature hot fluid
In case of coutercurrent flow configuration
Lmtd = ((Th1 – Tc2) – (Th2 – Tc1))/log((Th1-Tc2)/ (Th2 – Tc1))
While in case of parallel flow configuration
Lmtd = ((Th1 – Tc1) – (Th2 – Tc2))/log((Th1-Tc1)/ (Th2 – Tc2))
Please, does anybody of you know which is the expression in case of cross-flow configuration?
Thanks in advance





RE: Log mean TD
The LMTD correction factor for cross flow can be obtained from charts similar to the one shown here:
www.wlv.com/products/databook/ch4_3.pdf
Make sure you use the natural log in your calculation, not log(10).
-Christine
RE: Log mean TD