Reconsider Prob. 8–70. Using the EES (or other) software, evaluate the effect of glycerin mass flow rate on the free-stream velocity of the hydrogen gas needed to keep the outlet mean temperature of the glycerin at 40°C. By varying the mass flow rate of glycerin from 0.5 to 2.4 kg/s, plot the free stream velocity of the hydrogen gas as a function of the mass flow rate of the glycerin.

Data from problem 70

Glycerin is being heated by flowing between two very thin parallel 1-m-wide and 10-m-long plates with 12.5-mm spacing. The glycerin enters the parallel plates with a temperature 20°C and a mass flow rate of 0.7 kg/s . The outer surface of the parallel plates is subjected to hydrogen gas (an ideal gas at 1 atm) flow width-wise in parallel over the upper and lower surfaces of the two plates. The free-stream hydrogen gas has a velocity of 3 m/s and a temperature of 150°C. Determine the outlet mean temperature of the glycerin, the surface temperature of the parallel plates, and the total rate of heat transfer. Evaluate the properties for glycerin at 30°C and the properties of H₂ gas at 100°C. Are these good assumptions?

Transcribed Image Text:

H₂ gas flow 1m- Glycerin flow Parallel plates