Development Of A Fluid Mechanics Test Bench For Hydraulic Orifices And Ports Testing Under Both High And Low Temperature Conditions

With the increasing demand for modern hydraulic equipment to serve in extreme environments,it is urgent to study the basic theory of hydraulic fluid mechanics under high and low temperature conditions.Since the theoretical research of existing fluid mechanics is carried out and verified at room temperature,there are few studies on hydrodynamics under high and low temperature conditions,and there is no related experimental device.In this paper,the experimental methods and experimental devices under high and low temperature conditions are studied for common hydraulic orifices and gaps.The main research work is as follows:(1)According to the difficulties and requirements of hydraulic orifices and gaps under high and low temperature conditions,a new experimental method and device were proposed.Simulate the fluid flow of hydraulic orifices and slits through "test valves" of different structural sizes,and integrate "test valve" ? oil ? oil supply mechanism and some sensors into an "integrated experimental module".Then the "integrated experimental module" is installed in the high and low temperature chamber for experiment,which can effectively solve the problem of "test valve" and oil temperature control;At the same time,the "test valve" adopts the mechanical oil supply mode,and the oil supply can be realized simply and reliably under high and low temperature conditions,and the oil supply amount can be controlled.(2)The mechanical system of the test bench was designed:Including "integrated experimental module",mechanical gantry,structural design of the drive,as well as high and low temperature box and motor selection;The "test valve" simulating "hydraulic orifice flow" ? "parallel disc gap flow" ? "concentric annular gap flow" and "eccentric annular gap flow" were designed,and the main "test valve" was designed Dimensions.(3)The electrical and measurement control system of the test bench was designed:Including hardware selection,circuit design and layout,motor frequency control method and data acquisition design.The analog signals collected by the data acquisition card include displacement,load,temperature and pressure,all of which adopt differential input connection mode,which can effectively reduce common mode interference;In order to eliminate the interference of the strong electric equipment in the experimental environment,the signal line of the sensor is double-layered and insulated,and the signal is subjected to software filtering and hardware filtering.LabVIEW is used to develop the measurement and control software.The measurement control software can realize the automatic control and data acquisition of the experimental process,and can display,analyze and process the experimental data and save the output operation.(4)Hardware processing,integration and commissioning: Based on the electromechanical system design,the processing and integration of the test bench components were carried out,and the test bench was debugged to calibrate each sensor.The experimental tests of thin-walled small holes were carried out under the conditions of-30 °C,-20 °C,30 °C and 70 °C,and the flow-pressure characteristic curves and related experimental data were obtained.The original experimental methods proposed in the thesis and the experimental bench developed are of great significance for the study of the hydrodynamic characteristics of common hydraulic orifices and gaps under high and low temperature conditions.