Study on critical chocked characteristics of supercritical carbon dioxide spiral groove dry gas seal under thermal-fluid coupling lubrication
Under the premise of stable operation of the seal,promoting the formation of blocked flow at the seal end face outlet to increase the air film opening force and reduce end face leakage is an effective way to optimize dry gas sealing performance.Taking supercritical carbon dioxide(CO2)spiral groove dry gas seal as the object,the finite difference method was used to solve the pressure and temperature governing equations on the basis of the effects of real gas,centrifugal inertia,turbulence and chocked flow.The critical chocked characteristics(e.g.critical chocked inlet pressure po_cir,critical chocked speed N_cir,critical chocked film thickness h0_cir and chocked critical instability film thickness hsc)under thermal-fluid coupling lubrication were qualitatively studied.The results show that there is a chocked interval at the outlet of supercritical CO2 dry gas seal in isothermal and adiabatic model.The intervals corresponding to the inlet pressure,film thickness and rotational speed are po>po_cir,h0_cir<h0<hsc and N<N_cir,respectively.The increase of the rotating speed can continuously enhance the critical chocked inlet pressure and the critical chocked film thickness.The increase of the film thickness will lead to the decrease of the critical chocked pressure and the increase of the critical chocked speed.The high-pressure inlet will make the chocked zero stiffness corresponding to the film thickness(chocked critical instability film thickness hsc)down.Compared with the isothermal flow hypothesis,the influence of gas film thermal effect on the critical chocked characteristic parameters of supercritical CO2 dry gas seal is significant,and the influence rules are different.
supercritical carbon dioxidedry gas sealthermal-fluid couplingcritical choked characteristicschoked occurrence interval
万方数据
维普
