离心惯性力效应对超临界二氧化碳干气密封流场与密封特性影响分析

为揭示离心惯性力效应对S-CO₂干气密封流场与密封特性的影响规律，以螺旋槽干气密封为研究对象，引用考虑离心惯性力效应的Reynolds方程，在考虑气膜真实气体效应、黏度随压力与温度双重变化的同时，基于N-S方程与能量守恒定律，建立了绝热状态下考虑离心惯性力效应作用的能量控制方程. 然后，采用有限差分法对压力控制方程与能量控制方程进行耦合求解，并对考虑离心惯性力效应与没有考虑离心惯性力效应下的压力分布、温度分布以及密封特性进行了分析讨论. 研究表明:离心惯性力效应具有削弱流场内压力与温度的作用；从避免凝结流动角度考虑，离心惯性力效应引起的温降将不利于S-CO₂干气密封；考虑离心惯性力效应作用时，气膜开启力在不同槽深与转速下存在最佳工况点，泄漏率随着转速的增加显著减小，而离心惯性力效应与膜厚之间没有强交互作用；考虑离心惯性力效应作用的气膜开启力、泄漏率、出口温度均比不考虑离心惯性力效应作用的小，且这种差异随着转速的增大而增加，而随着膜厚的变化没有改变. 这些结果为进一步研究S-CO₂干气密封奠定了一定的理论基础. 

The Influence Analysis of Centrifugal Inertia Force Effect on the Flow Field and Sealing Characteristics of Supercritical Carbon Dioxide Dry Gas Seal

In order to reveal the influence law of centrifugal inertia force effect on the flow field and sealing characteristics of supercritical carbon dioxide dry gas seal, by using the spiral groove dry gas seal as the research object, the Reynolds equation considering centrifugal inertia force effect was cited. Considering the effect of real gas effect and viscosity of gas film with pressure and temperature changes, based on the Navier-Stokes equation and the law of conservation of energy, the energy governing equation considering the effect of centrifugal inertia force in adiabatic state was established. Then, the finite difference method was used to solve the pressure control equation and the energy control equation, and the pressure distribution, temperature distribution and sealing characteristics with and without centrifugal inertia force effect were analyzed and discussed. The research showed that the pressure and temperature in the flow field was weakened by the centrifugal inertia force effect. From the view point of avoiding condensation flow, the temperature drop caused by centrifugal inertia force effect was not conducive to S-CO₂ dry gas sealing. When the centrifugal inertia force effect was considered, the opening force of the gas film had the best working point at different depth and speed, the leakage rate decreased significantly with the increase of rotational speed, but there was no strong interaction between the centrifugal inertia force effect and the film thickness. Taking into account the action of centrifugal inertia force effect, the opening force, leakage rate, and outlet temperature of gas film were smaller than that without considering centrifugal inertia force effect, and the difference increased with the increase of rotating speed, but didn't change with the variation of film thickness. These results provided a certain theoretical foundation for further research on supercritical carbon dioxide dry gas seal.