Analysis of dynamic performance of crossflow heat exchangers for helicopters
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摘要: 滑油散热器的动态特性是直升机滑油冷却系统设计的基础,使用模块化集总参数法建立了直升机滑油散热器的动态仿真模型,采用Laplace变换建立动态传递函数,结合动态仿真模拟曲线的比较以及传递函数的分析,对热侧和冷侧入口温度阶跃变化时的热侧出口温度动态响应性能进行分析,得到了影响动态性能的重要影响参数——芯体蓄热时间常数τw以及热侧温度随流动时间τ变化的时间常数τh,从而可通过改变这两个重要影响参数来有效改变散热器以及系统的动态延迟时间.通过散热器动态实验测量,验证了模型的正确性.研究成果可有效改进散热器以及系统的动态性能,以及指导散热器与系统的优化耦合设计.Abstract: Modeling and simulation of transient heat transfer in crossflow heat exchanger are necessary for developing the oil system in helicopters. The dynamic model of crossflow heat exchanger was established by using lumped thermal controlled methods, and its accuracy was proved by dynamic experimental results of crossflow heat exchanger. Through analysis of dynamic performance of the crossflow heat exchanger, especially considered the dynamic response of the outlet temperature in the hot side to the change of the inlet temperature in the same side or the cold side. Based on the analysis of dynamic transfer function, the most important influence coefficients are obtained, which are regenerative time constant of core and time constant of temperature changing in the hot side along with flow time. By reducing the values of two most important influence coefficients, the dynamic detention time could be reduced efficiently. The dynamic performance of heat exchanger and the whole system also could be improved efficiently.
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Key words:
- simulation /
- heat transfer-fins /
- helicopters /
- dynamic analysis /
- parameter extraction
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