Effects of Heat Exchanger Characteristics on Optimized Intercooled Turbofan Engine Cycles

Abstract

The thermodynamic cycle of an intercooled turbofan engine was optimized by considering various characteristics of intercoolers (ICs). Sixty-three intercooled turbofan engines were optimized using an evolutionary algorithm. Thirty-nine design parameters were analyzed using proper orthogonal decomposition, and the effects of the IC performance on the engine thermodynamic cycle were examined. The improvement in net fuel consumption due to intercooling strongly depends on the characteristics of the IC fin, and the net fuel consumption is minimized at a particular fin height. By using ICs with an appropriate fin height, intercooling increases the overall pressure ratio, while increasing the heat transfer surface areas and cross-sectional areas of the ICs realizes high effectiveness and low pressure losses. The pressure ratio partition between the intermediate- and high-pressure compressors is determined according to incompatible characteristics of the IC, such as pressure losses and the temperature difference between the inlet and outlet of the IC. Because the weight of the IC is proportional to its fin area density, increasing the fin area density reduces the net fuel consumption. However, itdoes not significantly influence the thermodynamic cycle of the engine.