基于液力偶合器试验曲线的数学模型

在船舶动力装置稳、动态特性研究中,需要知道液力偶合器在任意工况下的力矩特性,但厂家提供的试验特性图只包含数条泵轮转速恒定情况下小滑差范围内输出力矩随涡轮转速变化的特性曲线。本文先根据液力偶合器的物理特性得出力矩外特性的解析式,再利用试验曲线提供的数据求出该解析式的系数,然后利用已知系数的力矩表达式,将泵轮转速恒定时的力矩试验特性曲线扩充到整个涡轮转速变化范围。最后将这些扩充了的力矩特性曲线进行曲面拟合,从而得出液力偶合器在任意输入泵轮转速和任意输出涡轮转速下的力矩特性,进而获得船舶动力装置仿真研究中液力偶合器完整的数学模型。

Mathematical Model of Fluid Coupler Based upon Physical Principle and Test Curves

On the research of static and dynamic characteristic of ship propulsion plant,it is necessary to know the torque characteristic of fluid coupler in any operating condition.However,only several characteristic curves,which describe the variation of output torque following turbine rotating speed in a narrow range of slip when the pump rotating speed is constant,are included in the test characteristic figure provided by manufacturer.In this paper,an analytical formula describing torque characteristic of fluid coupler is constituted on the basis of it's physical principle.Afterwards the unknown coefficients in the formula are worked out by using of the data derived from the test curves.Then the torque characteristic curves in the test figure are respectively extended to entire variation range of turbine rotating speed according to the foregoing torque formula whose coefficients have been known.Lastly surface fitting is conducted for these extended characteristic curves,which makes it possible to obtain the torque characteristic at any pump speed and turbine speed when ships are propelled,consequently making it easy to establish the mathematical model of fluid coupler on the simulation research of ship propulsion plant.