For a counter current heat exchanger with Ti h = 80°C, T°c = 60°C, T°h = 50°C and Ti c = 30°C, and the temperature difference between the two streams being the same everywhere along Z, the direction of flow of hot fluid. The temperature profile should satisfy___________________?

Question

Accepted Answer

d2T/dZ2 > 0. When the temperature difference is constant along Z, the rate of change of temperature with respect to Z (dT/dZ) must be increasing, meaning the second derivative (d2T/dZ2) is positive.