Study On Cylinder Wall Temperature Prediction

Pneumatic technology widely used in various fields along with the development of industrial automation. Practical applications often found that the larger type of cylinder with big load after a period of operation,the cylinder wall will appears chills or even be condensation on the surface, the smaller type of cylinder wall may occurs fever phenomenon after a period of operation. Research on cylinder wall chills and fever phenomenon, explain the reason of its occurrence, propose appropriate solutions to solve chilling and fever phenomenon to enhance the life of the cylinder and improve system performance has become an important topic.In this paper, we study on a large type of cylinder, we firstly proposed a new concept of equivalent thermal power to predict the cylinder wall temperature under different operating condition. Combined with experiments results we verified our prediction conclusions and finally we propose solutions for different working condition to solve or alleviate chill phenomenon.The main work of this paper are summarized as follows:(1) Using Simulink blocks to build the simulation platform. Establish a mathematical model which contains heat exchange between cylinder inside air and the cylinder wall, verify the correctness of the mathematical model.(2)Build experimental platform and use LabVIEW to setup the control system and the data acquisition for all the sensors. Combined with experiments to identify the parameters which required for simulation study. Calculate and derive the time constant method and use experiment data to get the average heat transfer coefficient between inside the cylinder inner wall surface and the gas in the cylinder.(3) Propose equivalent thermal power concept to study the changes in the cylinder wall temperature, equivalent thermal power cylinder model is based on the simulation results of a cylinder motion cycle, forecast cylinder wall temperature changes when the cylinder reach the steady thermal condition. Equivalent thermal power includes charge and discharge gas thermal power inside the cylinder and the friction heat power between cylinder piston seal and the cylinder wall. Charge and discharge gas thermal power is calculated based on the simulation of gas temperature, the friction heat power requires the measure of the friction and the heat distribution coefficient.(4) Calculate the equivalent thermal power under different working conditions, and predict the cylinder wall temperatures results, comparing prediction results and experimental results show that the equivalent thermal power is right to predict the cylinder wall temperature to a certain extent. Study the impaction of cylinder operating parameters on the cylinder wall temperature results and verify the results.(5) For different working conditions, propose methods to solve the cylinder wall temperature chills phenomenon. In the unidirectional load conditions, propose new solutions not only reduce the gas consumption but also we can effectively control the chills phenomenon. In the two-way conditions, we propose measures to increase the heat transfer area of the cylinder surface wall to relieve chills degree, simulation combined with experiments confirmed the correctness of the solution.