Numerical study on heat exchange performance for three-dimensional methane pre-cooler
A three-dimensional simulation method was established to assess the heat exchange performance with methane as coolant for an axial tube-bundled pre-cooler.The flow field of the pre-cooler was obtained at different coolant equivalent ratios and flight conditions,and the control strategy of coolant massflow was proposed from the simulation results.The assessed results indicated that the incoming air could be cooled 131 K at maximum under the condition of three times the equivalent ratio by methane pre-cooler,extending the working velocity spectrum to Ma=3.0 at least for conventional turbine engine.The air field could not completely well-distributed because of the influence of the tube arrangement which led to a maximum temperature distortion of 13.3％.The methane got a maximum temperature rise of 395 K.The temperature difference between the outside and inside tube surfaces was about 15 K,and the methane temperature range at cross section of the tube was about 10 K.The total pressure recovery coefficient of the pre-cooler was 0.715-0.88,the heat transfer efficiency was 0.63-0.9,and the maximum power-weight ratio was 395 kW/kg.The control strategy for coolant was proposed under the condition of engine pre-cooling requirement and coolant consumption limitation.It is recommended that the consumption of coolant should be restricted to 1.5 times the equivalent ratio as flight velocity was lower than Ma=2.5,and 3.0 times the equivalent ratio as flight velocity was higher than Ma=3.0.
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