Project ForgeHeat Transfer
Heat Exchangers
GATE 2020
Medium
A fluid is heated from 40°C to 60°C in a countercurrent double-pipe heat exchanger. Hot fluid enters at 100°C and exits at 70°C. The LMTD (°C) is (round off to 2 decimal places)
34.7 °C(± 0.5 accepted)
Explanation
Countercurrent pairing: ΔT1=100−60=40°C (hot-in/cold-out end), ΔT2=70−40=30°C (hot-out/cold-in end). LMTD=(40−30)/ln(40/30)=10/0.2877=34.76°C.
Source: GATE CH 2020 (2020)
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