热负荷变化对加热管内正十烷的振荡数值研究

摘要

Experimental study found that the supercritical endothermic hydrocarbon fuel system in supply process has produced oscillation.In order to further understand the mechanism of this phenomenon,two kinds of wall heat load regulation programs,linear change and step type change are prepared by using the decantation of the main component of hydrocarbon fuel as research object.Results show that the faster the wall heat load changes,the greater the overshoot value of outlet mass flow,the more significant temperature and velocity oscillations become.The larger the amplitude of thermal load is,the greater the oscillatory phenomenon of n-decane temperature field in quasi-critical range become,the greater the oscillation amplitude of velocity field and oscillation frequency are.The rate of change and amplitude of wall heat load can lead to oscillation of n-decane in quasi-critical temperature range,which can cause instability of fuel system supply.%通过实验研究发现超临界吸热碳氢燃料燃油系统在供给过程中产生了振荡现象,为了进一步认识这一现象产生的机理,采用碳氢燃料中的主要成分正十烷作为研究对象,分别编写线性变化和阶跃型变化的两类壁面热负荷调节程序,考察热负荷变化对正十烷动态特性影响.研究结果表明:壁面热负荷变化越快,其出口质量流量超调值越大,温度与速度振荡现象越显著;热负荷阶跃幅值越大处于拟临界范围内的正十烷温度场的振荡现象越显著,其速度场的振荡幅度越大,振荡频率也越高;壁面热负荷的变化速率与变化幅度都会引起拟临界温度范围内正十烷的振荡,从而造成燃油系统的供给出现不稳定现象.