Search

When designing the servo valve with different structure parameters, the influence of the interaction between the liquid and the solid on the performance of servo valve can only be obtain by the method of experiment, and then it can increase the time and cost of designing the servo valve. The liquid-solid couple method can obtain the influence of structure parameters on the performance of servo valve under the circumstance of reducing the experimental cost and time. The paper chooses the servo valve of A and B as models for study, The text adopts FSI method to analyze the flow field of double nozzle baffle electro-hydraulic servo valve prestage through the software of ANSYS, research the change of the prestage flow field by deflection of loaded armature baffle components, contrast and analyze the change of velocity, pressure, power loss and flow coefficient of fixed choke, nozzle, return port, and the displacement of the valve core of slide valve, stress of armature baffle components, pressure at both ends of spool. Summarize the advantages and disadvantages of A and B servo valve, and find different parameters of servo valve have different performance, it is difficult to find a common structure and size. It can help us to select the requirement structure by using fluid-structure interaction, reduce experiments and save cost.

Blow-off air nozzles blow away the residual emulsion from roll gap and strip surface. Algorithm SIMPLY were used for the finite element numerical simulation for a representational air nozzle blow-off flow field near the roll gap in a cold-rolled skin pass mill. The working conditions of the blow-off flow field was the combination of gas pressure of 0, 2, 5 and 10bar and flip angle of 0°, 5°, 10°, 15°, 20° and 25°. The study provides a reference for control and optimization for the removal process of residual emulsion and design, manufacture, model selection and optimization for the related air nozzles.

In order to ensure volumetric efficiency of low-speed and heavy-torque water hydraulic motor, the relationship between leakage flow and clearance of motor’s plain flow distribution pair in which water is used as medium is analyzed, and it’s concluded that the clearance of port plate and rotor end should be controlled below 5μm. In addition, the port plate flow field was simulated by using CFD software, and got that the leakage flow of numerical simulation is greater than theoretical calculation, and the numerical simulation values are more credible. It is also found that the maximum flow velocity is 16 m/s when outer ring is working, and when inner ring is working the maximum flow velocity is 20 m/s.

This paper analyses the flow of the double nozzle flapper valve. Three-dimensional model is established with software Pro/E, fluid analysis software is used for modeling and meshing, CFD method is applied for researching pressure, and flow characteristics of the fixed damping hole is researched when parameters of double nozzle flapper valve is varied. The results show that: the highest velocity through the fixed orifice hole is about 150m/s, the pressure is about 5.9MPa; Using orthogonal test to analyze the simulation results, it is obtained that the power losses of the double nozzle flapper with the change of the diameter, length and the angle of the fixed orifice, the influencing factors on the power losses are the diameter, length and the angle, and the best parameter combination through orthogonal table analysis is gained, which can provide the reference for the whole designing of the double nozzle flapper valve.

The oil pocket of the hydrostatic worktable in the modern heavy numerical control (NC) machine tools is designed under the circumstance that the working load acts equally on the oil pockets. But when the work piece is out of the rotary center of the worktable, the working load acts unequally on the oil pockets, and then the performance indexes for the oil pockets, such as acting force, oil film thickness, hydraulic damping, rated flow, are different. Based on the eccentric working load, under the circumstance that the oil pocket provides the fluid oil with constant pressure and constant flow mode, the coupling relationship between the oil pockets is analyzed, and the expression and the relatively bar graphics are presented. To achieve the machining quality and to prevent against the totally worn-out of the machine tools, it is best to adjust one oil pocket in order to keep the oil film of all oil pockets at the same thickness. While one oil pocket is adjusted, the oil pockets are intercoupling, and then the performance indexes change synchronously. According to the characteristics of the oil pocket in the hydrostatic worktable, the expression on the coupling relationship for the oil pocket is derived, then the performance indexes are analyzed qualitatively and the curves are plotted. The proposed research analyzed qualitatively the coupling relationship on the performance indexes for the constant pressure and the constant flow oil pockets separately in the worktable. It can improve the design efficiency and the accuracy with the help of the computer programs, and provides the reference for the practical engineering.

In this paper, The finite element analysis software is applied to compute the flow field in the fixed orifice with different structural parameter combinations, the pressure distribution curve, the velocity distribution curve, flow rate characteristic, power loss are obtained. By analyzing simulation results, the influence of the orifice parameters on the performance of the orifice is clear. The research is important for the design and optimization of the fixed throttle orifice of the nozzle-flapper valve.

Dynamic modeling was carried on by combining the dynamic of machinery with composite triology, and the critical condition in which the ways would not produce composite-friction self-excited vibration was obtained. The movement regularity and characteristic of the airflow in exhaust gas slit were analyzed, and the relationship between pressure lost and geometry parameters of exhaust gas slit was obtained. A dynamic model and a mathematical model were established for pneumatic half-floating slide ways by combining the dynamics of machinery with hydrokinetics. The objective function for the optimization of slide ways was established based on the fuzzy optimization theory. The membership function of fuzzy constraint was deduced, the fuzzy constraint limit was established by amplification coefficient method, and the optimal value was resolved by the multilevel fuzzy comprehensive evaluation method. By combining the internal penalty function method with the variable metric method, the fuzzy optimization design program of ways was designed based on the Matlab platform. The validation was carried on by an example, and ideal results of fuzzy optimization design of slide ways were obtained.