The simulation model of a valve control hydraulic system with long pipe isestablished in Simulink4.0, and then the step responses of the systems with difference pipeparameters are investigated by simulation. Simulatio...The simulation model of a valve control hydraulic system with long pipe isestablished in Simulink4.0, and then the step responses of the systems with difference pipeparameters are investigated by simulation. Simulation results show that the long pipes will slowdown the step response of system and make it fluctuate periodically. The results of simulationconform to the results of experiment on the whole, which proves the mathematic model is correct.展开更多
A test platform is established as per the practical working condition ofelevating platform fire truck. The influences of pipes and load on dynamic characteristics ofload-sensing system are studied by series of step re...A test platform is established as per the practical working condition ofelevating platform fire truck. The influences of pipes and load on dynamic characteristics ofload-sensing system are studied by series of step response experiments. Experimental results showthat the feedback pipe makes the most important influence on the dynamic response speed ofload-sensing system. Its internal diameter should be optimized for given length of pipe. On theother hand, the stability of load-sensing pump is improved as the length of input pipe increases ina certain range. The influence of input pipe on the dynamic response speed is caused mainly by thepressure-wave travel time in the input pipe.展开更多
A new effective technique, useful in telecommunications industry for passing an optical telephone cord attached to a connector through pipeline,has been developed using the spiral flow. Using this technique, the cord ...A new effective technique, useful in telecommunications industry for passing an optical telephone cord attached to a connector through pipeline,has been developed using the spiral flow. Using this technique, the cord could be passed through a straight pipeline 150 meters long and a roll of vinyl tube 50 meters long. However, under the same condition, the cord could not pass through when using the turbulent flow. To obtain a high speed stable spiral flow, a nozzle with an annular slit connected to a conical cylinder was used. A pressurized fluid with no tangential flow was supplied through this slit and the fluid, passing through the conical cylinder, was deformed into spiral flow with the steeper axial velocity distribution compared to that of turbulence pipe flow due to Coanda effect and instability. As a result, the cord was attracted to the axis area of the pipe, which effectively increased the ability for the work of cord passing. This high ability for cord passing is attributed mainly to the reduction of the friction made between the cord and the pipe wall, caused by the deformation to spiral flow.展开更多
A new laser inner wall hardening method for long pipe mas introduced. The system combines laser surface hardening with robot moving in pipeline. Some craft experiments have been done with this system and optimum param...A new laser inner wall hardening method for long pipe mas introduced. The system combines laser surface hardening with robot moving in pipeline. Some craft experiments have been done with this system and optimum parameters of laser hardening have been found.展开更多
基金This project is supported by National Natural Science Foundation of China(No.59875076).
文摘The simulation model of a valve control hydraulic system with long pipe isestablished in Simulink4.0, and then the step responses of the systems with difference pipeparameters are investigated by simulation. Simulation results show that the long pipes will slowdown the step response of system and make it fluctuate periodically. The results of simulationconform to the results of experiment on the whole, which proves the mathematic model is correct.
基金This project is supported by National Natural Science Foundation of China(No.59875076).
文摘A test platform is established as per the practical working condition ofelevating platform fire truck. The influences of pipes and load on dynamic characteristics ofload-sensing system are studied by series of step response experiments. Experimental results showthat the feedback pipe makes the most important influence on the dynamic response speed ofload-sensing system. Its internal diameter should be optimized for given length of pipe. On theother hand, the stability of load-sensing pump is improved as the length of input pipe increases ina certain range. The influence of input pipe on the dynamic response speed is caused mainly by thepressure-wave travel time in the input pipe.
文摘A new effective technique, useful in telecommunications industry for passing an optical telephone cord attached to a connector through pipeline,has been developed using the spiral flow. Using this technique, the cord could be passed through a straight pipeline 150 meters long and a roll of vinyl tube 50 meters long. However, under the same condition, the cord could not pass through when using the turbulent flow. To obtain a high speed stable spiral flow, a nozzle with an annular slit connected to a conical cylinder was used. A pressurized fluid with no tangential flow was supplied through this slit and the fluid, passing through the conical cylinder, was deformed into spiral flow with the steeper axial velocity distribution compared to that of turbulence pipe flow due to Coanda effect and instability. As a result, the cord was attracted to the axis area of the pipe, which effectively increased the ability for the work of cord passing. This high ability for cord passing is attributed mainly to the reduction of the friction made between the cord and the pipe wall, caused by the deformation to spiral flow.
文摘A new laser inner wall hardening method for long pipe mas introduced. The system combines laser surface hardening with robot moving in pipeline. Some craft experiments have been done with this system and optimum parameters of laser hardening have been found.
