Advanced Materials Research Vols. 201-203

Abstract: The reciprocating rectilinear moving mechanism is applied widely in the industry, which is now usually driven by the non-symmetrical mechanism. Due to the changing radial force generated by the slider, the big friction loss and the vibration noise are caused. And, the size of travel in reciprocating motion is fixed and can not be adjusted. In order to overcome these defections, the reciprocating rectilinear moving mechanism at high frequency driven by the stepper or servo motors based on two symmetrical cranks is innovated in this paper, in which the linear movement is converted by the two cranks. The radial forces in this innovated mechanism are quite symmetrical and balanced, so the friction loss can be almost ignored and the oscillation noise is very small too. Then, through programming, the angle range of stepper or servo motors can be controlled to output any required displacement and any required force. Thus, the scope of application of this mechanism is expanded extremely.

Abstract: A new structure of hydraulic hybrid vehicle (HHV) with hydraulic transformer (HT) was built and the working principle of the new hydraulic hybrid vehicle was described. According to the operating characteristics of HT and energy-saving optimization conditions of accumulator used the HHV; Energy-saving optimization control algorithm with various operation conditions in different working conditions of vehicle was established. Then, simulation analysis to control performance of energy-saving algorithm was carried out using PID, Fuzzy Logic Controller (FLC) and Fuzzy-PID control strategy. Results show that Fuzzy-PID controller has a small influence on the parameters of energy-saving optimization algorithm of the hydraulic hybrid vehicle and maximizing energy recovery can be achieved in different energy states by Fuzzy-PID controller.

Abstract: A new type of device of laminar water draining with no external force is proposed in this essay which established the physical and mathematical models of laminar water draining so as to make the oil-water mixture, in the use of different density under the laminar water, have different buoyancy in vertical direction to reach the separation of oil and water; at the same time, due to the design of the spring-loaded throttle control device, adjusting the flow rate to achieve laminar flow; using the fact that different densities of oil and water resulting different pressure, it formed the oil water interface pressure which provided power of water draining, and through float level static and dynamic state, it controlled solenoid valve opened and closed to achieve the automatic draining of water.

Abstract: This paper reported characteristics of gas-solid two-phase flow for a Y-shaped branch pipe. Y-shaped branch pipeline with one fixed and one adjustable branch angle was built up. Micro-glass bead and millet particles with similar diameter and different solid density were conveyed in this experimental system. As a result, trend of solids mass ratio flowing in changeable branch was used to predict flow distribution characteristics experimentally. It was found that the solids flow distribution of the two materials had similar trend and were significantly affected by the branch angle and gas velocity. Finally, a calculating equation to predict the solids flow distribution of branch pipe was achieved based on experimental data, which had good accuracy.

Abstract: This work concentrated on being able to predict the resistance properties of Y-shaped branch pipe in gas-solid two phase flow. Y-shaped branch pipeline with one branch angle keeping constant and the other being changeable experimental system was built up. Micro-glass bead and millet with similar particle diameter and different solid density were conveyed in the experimental system. As a result, trends of pressure drop on each branch pipe were expressed to perform resistance properties. It can be concluded that pressure drop of the two materials had similar trend and was significantly affected by the branch angle and gas velocity. Meanwhile, the deposition velocity was defined in this study. The relationship between the solids loading ratio and pressure drop on each branch pipe was given based on experimental data, which agreed the theoretical analysis well.

Abstract: According to the conception of symmetric beauty in the aesthetics, a new kind of numerical control press with double operating positions based on lever-toggle force amplifying mechanism driven by linear servo motor is introduced here. Its working principle, characteristic features and mechanical calculating formulas are given also. Compared with traditional mechanical press based on the crank-linkage-slider mechanism driven by common AC motor, the system has following advantages: two operating positions, higher energy transmission and production efficiency, no environmental pollution; lower cost of machine tool. Through rationally designing the acceleration curve of the pressure head, the impacting noise of the system can be reduced greatly. This press is especially suitable for blanking and low-stretching process.

Abstract: Hydraulic transmission clamping device may cause environmental pollution due to the existing of fluid pump and open oil tank. A new-concept clamping device based on high flexibility of hydraulic is introduced in this paper. Without any pump and open oil tank, environments pollution is reduced to a very low level. The driving piston is actuated by combined wormgear and crank-slider mechanism, the clamping piston is driven by sealed fluid in the two cylinders. The self-locking wormgear provides continuous clamping force during machining without any added energy, and a pressure switch guarantees the safety of operation. There are many choices when we considering the power sources, it could be electrical motor with proper speed reducer or just manpower, which provide a rotation movement. The working principle and mechanical calculation formulas are presented in this paper, which is instructive to the industrial field.

Abstract: With the rapid development of modern industry, more and more high requirements for forging velocity and control precision have been proposed. Because it can not only increase productivity, but also can reduce the loss of the workpiece and save raw materials. Due to some characteristics such as high pressure, large flow, heavy moving inertia and so on, the process control performance of the fast forging hydraulic presses often have difficulty in their coordination between rapidity and stability, large shock during pressure relief and flow relief, low control accuracy and high accident rate. To overcome the negative influence and improve forging press performance, it is important to design forging curve. 22MN fast forging hydraulic press adopts electro-hydraulic proportional control system, the simulation and test results approved that the fast forging hydraulic press has high control accuracy and works stably without shock.

Abstract: This study discuss the distribution of the flows when the forced convection impacted on the spin and the static in table tennis; the research method is using the thermal flow in the experiment which the thermal flow will reflect according to the imaging principle when it passes through the spin sphere; this can be used to simulate the flows of balls in static condition and backspin ball in high-speed and low-speed rotation; the air flow passes through the spin sphere and generates the ball pressure which forms the quality variation of the spheres in table tennis competition; the results showed that it has a lower drag force, low fluid momentum and lower rectilinear speed when the sphere is in static condition , low Reynolds number; on the contrary, it has a higher drag force and increasing rectilinear speed of flows when the Reynolds number is high. When the ball is in backspin condition, the flows are symmetrical presented, and then the flows are gradually distributed, asymmetrical presented and are upward. The higher the Reynolds number is, the smaller the wake region is due to that the forced convection effect increased; the smaller the Reynolds number is, the ball will have more significant spin kinetic energy increasing rate when the spin speeds up.

Abstract: The main bearing chamber is a major part of the lubrication system in aero-engine, it is important to know the influence of operation parameters on air/oil two-phase flow, so as to optimize the design of aero-engine lubrication system. The air/oil two-phase flow in a simplified bearing chamber model in an aero-engine is simulated by means of discrete phase model (DPM) and wall-film model with CFD approach. The simulation results coincide with the existing experimental data. The oil film thickness and concentration of droplets in bearing chamber are presented at different rotational speeds and different lubricating oil flow rates.