Question

8. The oil in a hydraulic power supply is cooled using a water-ol hel u The fow on both sides of the heat exchanger is turbulent and of a constant volumetric fow rate. As the oil heats up most of its properties remain constant, but the viscosity rapidly and significantly decreases with increased temperature. What is true about the heat exchanger as the oil heats? O The pressure drop across oil side of the HX becomes significantly smaller. O The power flow across the HX increases in direct proportion to the log-mean tem- perature difference between the water and the oil. O The power flow across the HX increases more rapidly than the log-mean temperature difference between the water and the oil. O The power flow across the HX increases in direct proportion to the log-mean tem- perature difference between the water and the oil, and the pressure drop across the oil side of the HX becomes significantly smaller O The power low across the HX increases more rapidly than the log-mean temperature difference between the water and the oil, and the pressure drop across the oil side of the HX becomes significantly smaller

Answer 1

The power flow across the HX increases in direct proportion to the log mean temperature difference between the water and the oil, and the pressure drop across the oil side of the HX becomes significantly smaller.