Question

A regeneratively cooled liquid rocket engine plans to use film cooling in the chamber to minimize the heat flux to the wall. Tests on a heavyweight chamber reveal a gas-phase heat transfer coefficient of 15.0 W/mÂ²-K in this low-velocity region. The liquid temperature rise has been measured to be 30Â°C under a mass flow rate of 3 kg/s (per tube). Details regarding the liquid, wall, and gas properties (assumed to be constant) are tabulated below, while the figure below shows the chamber and tube geometry for the test. Calculate the wall temperature on the gas side, Twg. Estimate the pressure drop in the channel between stations 1 and 2 noted below. Suppose the Twg value you calculate is much too high. Suggest a way to lower Twg with minimum performance penalties. Tube cross-section Tube coolant passage K12 All dimensions 0.8 cm ATo 30Â°C Injector 0.5 m Coolant in 0.05 cm (All sides) Mt^ Liquid RP-L properties: p = 700 kg/mÂ³, Cp = 1.88 J/kg-K, k = 0.133 W/m-K, L = 0.55 centipoise Gas chamber properties: Pc = 1.3 kg/mÂ³, Tc = 2900 K, m = 200 kg/s, Pr = 0.6 Wall properties (SS): p = 8130 kg/mÂ³, Cp = 434 J/kg-K, k = 40 W/m-K

          A regeneratively cooled liquid rocket engine plans to use film cooling in the chamber to minimize the heat flux to the wall. Tests on a heavyweight chamber reveal a gas-phase heat transfer coefficient of 15.0 W/mÂ²-K in this low-velocity region. The liquid temperature rise has been measured to be 30Â°C under a mass flow rate of 3 kg/s (per tube). Details regarding the liquid, wall, and gas properties (assumed to be constant) are tabulated below, while the figure below shows the chamber and tube geometry for the test. Calculate the wall temperature on the gas side, Twg. Estimate the pressure drop in the channel between stations 1 and 2 noted below. Suppose the Twg value you calculate is much too high. Suggest a way to lower Twg with minimum performance penalties.

Tube cross-section
Tube coolant passage
K12
All dimensions 0.8 cm
ATo 30Â°C
Injector
0.5 m
Coolant in
0.05 cm (All sides)
Mt^
Liquid RP-L properties: p = 700 kg/mÂ³, Cp = 1.88 J/kg-K, k = 0.133 W/m-K, L = 0.55 centipoise
Gas chamber properties: Pc = 1.3 kg/mÂ³, Tc = 2900 K, m = 200 kg/s, Pr = 0.6
Wall properties (SS): p = 8130 kg/mÂ³, Cp = 434 J/kg-K, k = 40 W/m-K

a regeneratively cooled liquid rocket engine plans to use film cooling in the chamber to minimize the heat flux t0 the wall tests on a heavy weight chamber reveal a gas phase heat transfer c 13506

Added by Thomas O.

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