Development And Performance Analysis Of Reciprocating Seal For Flexible Shaft

Flexible shaft is widely used in aerospace,chemical and many other fields due to the better resilience performance after deformation.However,the sealing problem is particularly prominent in reciprocating motion on account of the characteristics of surface imperfection and flexible deformation.Thus,a reciprocating seal for flexible shaft was designed with the advantages of adjustable,self pressurization and low energy consumption and a national invention patent was applied.The static and dynamic performance were studied systematically by finite element analysis together with experiments.The static finite element model of the reciprocating seal for flexible shaft is established by using ABAQUS.The deformation and stress distribution of the seal and flexible shaft were analyzed under the static conditions,including pre-assembly and exerting pressure.The technical indexes for evaluating the static performance of the reciprocating seal for flexible shaft were determined.They were the strength safety margin,contact stress margin and static friction force margin,which reflected the intensity,static sealing performance and start-up performance.The influence of working parameters and structural parameters on static performance was studied.The results show that with the increasing of control pressure the intensity and start-up performance of the seal are reduced,and static sealing performance is increased.The medium pressure,to a certain extent,can improve the intensity and start-up performance of the seal.The effects of the structural parameters,such as the pressurize coefficient,the deformation coefficient and the clearance coefficient,on the static performance were studied by using single parameter and orthogonal optimization method.The dynamic finite element model of the reciprocating seal for flexible shaft was established.The characteristics of deformation and stress distribution were compared with that in static state.The technical indexes for evaluating the dynamic performance were presented,They were leakage rate,dynamic friction force and sealing power consumption.The effect of control pressure and medium pressure on dynamic performance was studied.The results show that the leakage rate is reasonable when the control pressure exceed the medium pressure.The dynamic friction force and the sealing power consumption increase linearly with the control pressure,and decrease linearly with the medium pressure.The dynamic relationship between the control pressure,the medium pressure and the leakage rate was analyzed comprehensively.The corresponding relation among the three was obtained,and the correlation formula was fitted.According to the conclusions of static and dynamic performance,a design method of the reciprocating seal for flexible shaft was summarized.The design time and cost are reduced,and the design cycle is shortened.The experiment system of the reciprocating seal for flexible shaft was developed,and the friction force and sealing performance experiments were completed.It is proved that the reciprocating seal for flexible shaft has good sealing performance and operating performance in practical conditions.The experiment results were compared with the results of the finite element analysis,and the validity of the finite element analysis is verified.By studying the performance of the reciprocating seal for flexible shaft,the advantages of reciprocating seal of flexible shaft is verified.The successful development of the reciprocating seal for flexible shaft provides a new idea for high pressure and high speed reciprocating seal technology and accumulates experience for flexible shaft seal technology.It makes a certain contribution to improve the performance of reciprocating seal and expand the scope of engineering applications.