燃-滑油换热器壳侧换热特性研究

A Study of Heat Transfer Characteristics on Shell-Side of

关键词:  航空发动机  动压式油气分离器  含气率  分离性能

Key words:  Heat transfer coefficient  Bubbly flow  Gas-liquid two-phase flow  Fuel-oil heat exchanger

摘要:

针对航空发动机滑油系统所使用的小管径燃-滑油换热器，开展了壳侧换热特性实验研究。研究表明:当壳侧为滑油单相流时，壳侧对流换热系数可以采用Kern经验公式计算；在换热器可能的工作范围内，壳侧气液两相流流型为泡状流；保持液相折算速度(或气相折算速度)不变，两相对流换热系数随气相折算速度(或液相折算速度)的增大而增大，相同液相速度时，两相对流换热系数要大于单相，最大可达2.3倍；最后根据泡状流特点，基于L-M模型给出了壳侧两相换热系数计算公式，计算平均相对误差为3.6%，可满足工程需要。

Abstract:

An experimental research of heat transfer characteristics on shell-side is carried out for the small diameter fuel-oil heat exchanger used in aviation engine oil system. Research shows that convective heat transfer coefficient on shell-side can be calculated using Kern empirical formula when the shell-side has single-phase oil. In the working range of heat exchanger，gas-liquid two-phase flow on shell-side is bubbly flow. Convective heat transfer coefficient of two-phase flow increases with the increase of gas superficial velocity (or liquid superficial velocity) when liquid superficial velocity (or gas superficial velocity) are held constant. Convective heat transfer coefficient of the two-phase flow is greater than that of the single-phase flow in the same liquid phase velocity，and the maximum is up to 2.3 times. At last，according to the characteristics of bubbly flow，a calculation formula of the two-phase convective heat transfer coefficient on shell-side is provided based on L-M model. The average relative error is about 3.6%，which can satisfy the engineering demand.