Handling improvement of the M1 class vehicles by the way of hydraulic power steering adaptive characteristic optimization

In the paper, a work on handling improvement of the M1 class vehicle by means of optimization of the volume flow-pressure characteristic of the power steering pump with adaptive characteristic is described. A work on the simulation of the liquid flow through the electromagnetic valve of the power steering pump in initial and modified state is described. Results of bench testing of the optimized pump prototypes and subjective and objective road tests of the M1 vehicle with optimized prototype and initial one installed are presented.

Simulation of a downhole jet-vortex pump’s working process

The article is devoted to the theoretical study of the operation process of the borehole ejection system as part of the tubing string, jet pump and packer installed below; the system implements the hydrojet method of oil well operation. The improved design of the jet pump contains inclined guiding elements placed in its receiving chamber for swirling the injected flow, which results in an increase in the efficiency of the borehole ejection system. Based on the law of conservation of liquid momentum in the mixing chamber of the jet pump and taking into account the inertial pressure component caused by the swirling of the injected flow, there is obtained the relative form of the equation of the ejection system pressure characteristic, the structure of which contains a component that determines the value of the additional dynamic head. According to the results obtained, the additional dynamic head caused by swirling of the injected flow is determined by the ratio of the geometric dimensions of the flow path of the jet pump, the angle of inclination of the elements for creating vortex flows, and the ratio of the power and reservoir fluids. In the case of asymmetric swirling of the injected flow, an increase in the value of the relative displacement of the jet pump decreases the value of the additional dynamic pressure. In order to study the effect of flow swirling on the energy characteristic of the ejection system, the pressure characteristic of the jet pump was transformed into the dependence of its efficiency on the injection coefficient. Jet pump models with the ratio of the cross-sectional areas of the mixing chamber and the nozzle of 5.012 and 6.464, respectively, were used to check the adequacy of the theoretical pressure and energy characteristics obtained during the simulation of the performance process of the concentric ejection system. The average error in the theoretical determination of the pressure and efficiency of the vortex jet does not exceed 8.65% and 6.48%, respectively.

Methodology for Analyzing the Actual Technical Condition of Downhole Pumping Equipment

The reducing in the pressure characteristic of the submersible pump during operation occurs as a result of the combined action of a number of reasons. Pumping equipment wears out due to waterjet destruction of flow channels. The characteristics of submersible pumps are captured at the factory on special stands. At large group groundwater intakes, wells are equipped with an automated control system that allows testing the pump at the workplace and promptly making a decision on its replacement if the pressure characteristic is unacceptably reduced. The actual pressure characteristic of the pump H н = f (Q) can be plotted directly in the well with a sufficient degree of accuracy. To determine the degree of wear of the pump, its pressure characteristics are compared before installation and at the time of taking readings. The article describes a well strapping scheme for measuring the specific flow rate and pressure characteristics of a submersible pump. The purpose of the study is to derive a dependency for constructing the flow-pressure characteristics of a submersible pump at its workplace and to develop a method for accounting for its wear during operation, which allows predicting a decrease in well productivity over time. An expression is proposed to describe the characteristics of the pump at any time, calculated from its installation in the well. The analysis of the reducing in the pressure characteristics of pumps produced by various manufacturers in the wells of the existing water intake of underground water is presented. It is confirmed that the intensity of the pressure reduction depends on the duration of the pump operation in a given well, the material of the pump impellers and the sand content in the pumped water.

Experiment analysis of high output pressure piezoelectric pump with straight arm wheeled check valve

Piezoelectric pumps are applied in many fields, such as chemical analysis system and fluid pumping systems. Piezoelectric pumps with high output pressure can meet the needs of more fields. This article introduces the design and fabrication of a high output pressure piezoelectric pump with straight arm wheeled check valve. In this paper, the influence of straight arm wheeled check valve on the output pressure of piezoelectric pump is deeply discussed from the aspect of energy loss. This study investigated the effect of valve arm number ( N = 2, 3,4, and 5), the valve arm width ( W = 0.8, 1.0, and 1.2 mm), and the valve arm length ( L = 1.92, 2.02, and 2.12 mm) on the output pressure of piezoelectric pump. The output pressure characteristic of straight arm wheeled check valve piezoelectric pump with different valve parameters is obtained by experiment. Experimental results show that when N = 4, W = 1.0 mm, L = 2.02 mm, the output pressure of the straight arm wheeled check valve piezoelectric pump has the best output pressure of 27.41 kPa at 220 V and 85 Hz. This study provides a reference for the further application of piezoelectric pumps in fluid pumping field.

The structure and pressure characteristics of graduated compression stockings: experimental and numerical study

The incorporation of pressure levels and pressure gradients in the design of compression stockings offers excellent potential to enhance function in the sport science, clinical research and rehabilitation fields. Yet, the connection of processing parameters and structure accompanying the pressure characteristic of current graduated compression stockings (GCS) is not well quantitatively studied. To bridge this knowledge gap, this study aims to analyze the effects of processing parameters, such as elastane yarn count, loop length and elastane feeding tension, on the structure and pressure behavior of GCS in our work. In addition, to investigate the mechanism of the pressure characteristic, two numerical models, the cylinder model and the conical model, are employed to predict the pressure value and the pressure gradient of stockings. The experimental results of the statistical analysis indicate that the loop length is a key factor to control the wale density, length of stockings and final pressure values. Moreover, the elastane feeding tension could affect the course density, girth of stockings and pressure gradient. On the other hand, the numerical results reveal that the conical model is suited for predicting the pressure values because of the change in radius of the limb in the model. The entire experimental and numerical work provide the mechanism for the study basis of processing, structure and pressure characteristics of GCS.

Impact System Dynamic Characteristics of Hydraulic Rock Drill Based on an Overlapped Reversing Valve

For the phenomenon of a hydraulic rock drill based on an underlapped reversing valve, the mechanical structure of the overlapped reversing form was proposed, which affected the pressure pulsation of the impact system, and motion of the impact piston was analyzed. The model of a hydraulic rock drill was built based on Newton’s laws. The initial lead size of the reversing point was calculated by the equilibrium position of the damping piston and final velocity of the impact piston. The size of the overlapped reversing valve was designed and the best impact interval was calculated, according to pressure characteristic curves in the piston of the front-rear chamber and in the reversing valve of the left-right chamber, and the damping piston floating feature had an impact on initial lead size of the reversing point. The advantages of the overlapped reversing valve were analyzed, by contrasting the pressure pulsation of the impact system and motion of the impact piston with the underlapped reversing valve. The inner mechanism experiment of the hydraulic rock drill was designed to test the pressure characteristic curves in the piston of the front-rear chamber and in the reversing valve of the left-right chamber. The model of the overlapped reversing valve was verified by the experiment.