高压气瓶充气过程温升规律研究

Trace and analysis of the temperature rise in a high-pressure vessel in the process of refueling

为得到某型航天发射器高压气瓶长时间充气过程中温度变化的规律,研究了气瓶在绝热条件下的充气过程,利用热力学基本理论计算了充气过程的理论最高温升;综合应用气体动力学理论和变质量系统热力学知识提出了一种计算实际充气过程温升的新方法,即将充气过程划分为多个阶段,并以压力试验数据为基础,依次计算各个阶段的相关参数,以此方法对气瓶充气过程的温升进行了计算并对其温升规律进行了初步讨论。结果表明,在充气过程的初始阶段,传热效应较弱,气瓶温度急剧上升,之后传热效应逐渐增强,气瓶温升逐渐平稳并最终有所下降。为此以传热学知识为基础建立了气瓶充气过程的热力学模型,采用大空间自然对流换热热力学模型使研究更接近于实际工况。以此模型对充气过程中气瓶内的参数变化情况进行数值模拟计算,并将压力数值计算值与试验值、温度数值计算值与理论计算值进行比较。结果表明,在开始充气约10min时气瓶温度达到最大值(略低于80℃),且该热力学模型能够基本反映气瓶在充气过程中气瓶内气体的热力学过程。

The present paper is to introduce our observation and ana-l ysis results of the trend of temperature change during the long-refilling process of a high-pressure vessel fixed on the rocke-t propelled spacecraft. In doing so, we had first of all studied the adiabatic filling process and analyzed howthe highest temperature has been reached during the process based on the theory of thermodynamicswith some theoretical reference to the diabatic filling process. Secondly, we have worked out a new method based on the thermodynamics of variable mass systems and the gas kinetics theories, by dividing the filling process into necessary parts and calculating the parameters of every part based on the experimental pressure data. And, then, with the method we have renovated, we have made sure the temperature change situation during the filling process, and detailedly analyzedthe trend of temperature change. The calculated data indicate that the temperature of the gas in the cylinder tends to increase rapidly at the initial stage due to the weakness of heat transfer during the filling, then it would arrive at the state of stabilization, and finally it would begin to decline slightly because of the stronger heat transfer. It is in this way that we have successfully founded the thermodynamic model to numerically simulate the temperature variation of the filling process based on the hea-t transfer theories. And, later, we have adopted the natural convection during the numerical simulation to make the simulation by imitating the authentic process and numerically calculated the change of the parameters of the gas in the cylinder duringthe process. And, now, we have made a comparison between the simulated data of the pressure with those we have gained from the experimental process, the results of which show that the highest temperature, under 80℃, would emerge at about 10 min afterthe refilling began and this thermodynamic model could reflect the thermodynamic process of the gas in the cylinder. Hence, the present research can probably help to lay a foundation for pursuing the relation among the temperature rise, the initial parameters and the layout of the fast filling control algorithm.