Universal approach to the description of working medium chambers for simulating hydraulic and pneumatic systems

The article is concerned with the consideration of methods of mathematical formulation of processes in interthrottle chambers and working medium reservoirs used to simulate the operation of hydraulic and pneumatic systems.

Consideration has been given to a general approach to the development of mathematical models of hydraulic and pneumatic systems; the stages of constructing models are also presented.

A generalized mathematical model of a heat-insulated chamber with variable volume is presented. The derivation of standard mathematical modules of the above chamber on the basis of the generalized model is given. The assumptions taken into consideration with the existing methods of describing the processes taking place in chambers and reservoirs of hydraulic and pneumatic systems are analyzed. The shortcomings of the existing methods are shown.

An approach to forming a mathematical formulation is proposed, which is universal in its nature and reflects the processes under consideration in full measure. The proposed description method is based on the laws of conservation of thermodynamics of a variable-mass body. A special record of thermal and caloric equations of the state model makes it universal and independent of the working medium type. When compiling the digital models of chambers, both equations of working medium state and tabulated reference data can be used.

 Design diagrams and mathematical models of heat-insulated chambers with variable and constant volumes are presented as an example. A digital model is presented and the results of modeling the operation of hydraulic and pneumatic actuators performed with the use of the proposed method are given. The digital model is implemented in the training version of the Russian software package “Simulation in technical devices”.