Numerical Simulation And Control System Of Spiral Groove Dry Gas Seal

In the field of petrochemicals,most of the toxic or flammable and explosive substances are handled,and the leakage of flammable and explosive gases under high temperature and high pressure conditions will cause fires and explosions,which will directly cause casualties and economic losses.To this end,it is necessary to carry out technical research on sealing and to cultivate talents in sealing to achieve the goal of safe production.In recent years,with the development of sealing technology,a new type of seal using gas as a sealing medium has appeared in petrochemical production.The seal no longer uses the complex oil seal auxiliary system required by the traditional oil seal,and realizes the non-contact operation of the dynamic seal,so-called dry operation.The sealing medium of the seal is gas.As a new type of non-contact gas shaft end seal,dry gas seal has many advantages over traditional seals: no wear operation,low power consumption and low leakage.Many rotary machines,such as pumps,compressors,and expansion machines,use dry gas seals.Therefore,carrying out domestic research on dry gas sealing technology is of great practical significance for China to improve the production safety and equipment use efficiency of the petroleum,chemical and gas industries.In this thesis,Fluent simulation calculation is carried out on a dry gas sealing device with different specifications,different pressures,inner and outer diameters,and different sealing gas medium conditions.From the three performance indicators of leakage,gas film rigidity and rigid leakage ratio In terms of parameters,analyze the influence of various variables on dry gas sealing performance.Then,based on the principle of single variable,theinfluence of geometric parameters on the performance of dry gas sealing was explored,and the influence rules of different geometric parameters on dry gas sealing were obtained.Finally,based on the requirements of seal gas cleanliness,pressure and flow control,the basic composition and function of each part of dry gas seal control system are analyzed,and the basic requirements of dry gas seal operating conditions and seal function control are described.According to this,the design of the dry gas seal measurement and control system was completed,the statistics of the control points and measurement points were completed,and the various modules of the PLC were selected.Through the connection between the instrument,valve and PLC and the software program,the PLC adjusts the valve according to the pressure and flow signals,and controls the corresponding parameters of the sealing gas and isolation gas to meet the requirements of the dry gas seal,ensuring the reliable and safe operation of the dry gas seal.The dry gas sealing device plays a vital role in the safe and stable operation of the entire centrifugal compressor.Therefore,the research results of this paper have important practical significance for the safe operation of the dry gas sealing system and for the independent design of the equipment.