Influence of high temperature degaussing on lifting capacity of linear motor reciprocating pump

The submersible linear motor reciprocating pump is a new type of artificial lift. The degaussing effect of its permanent magnet at high temperature will reduce the lifting capacity of the linear motor reciprocating pump. In this paper, the thermal stability of NdFeB permanent magnet material was studied by simulating the underground temperature and pressure conditions in a high-temperature and high-pressure reactor and combining with a Tesla instrument. The results show that NdFeB material loses its magnetism rapidly at high temperature, and the residual magnetism is proportional to the ambient temperature of the magnet. The high temperature demagnetization effect of large magnets is more serious due to eddy current loss and hysteresis loss.

Simulation of Unsteady Flow Characteristics of the Reciprocating Pump Check Valve for High Pressure and High Flow Water Medium

The distribution efficiency of the check valve directly affects the performance of the reciprocating pump. The flow coefficient is an important evaluation criterion for the flow capacity of the valve port, and it is of great significance to the design of the valve structure and even the control of cavitation. The traditional design uses flow coefficient as a fixed value, however, the flow state and flow coefficient will change during valve movement. In this study, a three-dimensional transient computational fluid dynamic model for high-pressure and large-flow reciprocating pump valve is established. The dynamic grid simulation method of coupling for the valves and plunger is innovatively proposed, and experimental verification was carried out. The flow state and pressure characteristics for the suction valve under high outlet pressure are analyzed, and the change rule of the suction coefficient is found. The research results show that the initial pressure of the plunger cavity prolongs the negative pressure duration of the plunger cavity when the valve is opened and increases the risk of cavitation of the valve. During the process from valve opening to maximum lift, the suction coefficient first increases and then decreases, and finally remains between 0.5 and 0.6. When the valve lift is large, two-stage throttling occurs, and the flow state will change from cylindrical jet on the lower surface of the valve disk to annular jet, which is beneficial to improve the suction coefficient.

Simple and Efficient Methods to Perform the Optimum Matching Between a Reciprocating Piston Pump and a Wind Machine

One of the major problems facing the use of the wind driven reciprocating lift pump is the problem of starting. The required starting torque of the pump is at least three times the average torque. This means that the pump will need a high wind velocity just to be started, after that it will continue to operate at a lower wind velocity because of the lower average torque, provided that there is enough inertia in the system. For this reason, the torque characteristics of the wind turbine – reciprocating pump combination are very important. Thus, there is a real need to develop new methods in order to reduce this starting performance of the reciprocating pump. This paper presents a theoretical study to reduce the starting torque of a non-conventional reciprocating piston pump using new methods, for example, changing the wind machine parameters, such as the aerodynamics configuration of the rotor and blade elements, or by studying the effect of wind speed velocity on the starting torque. Also by changing the cross-section area of the piston or by changing the static head of the piston pump or by controlling the flow rate of the piston pump.

Performance Characteristics of a Reciprocating Piston Pump Driven by a Wind Machine

The torque applied by a reciprocating pump on a wind machine axis is a fluctuating torque. The energy furnished by the pump on the wind machine axis is absorbed mainly in raising the water and the piston when the latter moves up. This has a direct adverse effect on the starting speed. The lower the maximum torque to be overcome, the easier will the wind machine start. If the necessary torque is high, a faster wind speed is required to start the wind machine. The operating time of the machine is consequently reduced. It is therefore desirable to reduce the starting torque, and hence to make the starting easier. This paper presents a theoretical study to reduce the starting torque of a non-conventional reciprocating piston pump by controlling the stroke volume of the pump or by controlling the flow rate of the piston pump. These two methods are the best to control, smooth and reduce the starting torque of the pump by drilling a very small hole in the piston. The effect of this hole is that at very low speed (at starting) all water that could be pumped is leaked through the hole. This is the main important of the hole which made the pressure on the piston is very low and as a result the starting torque is low. The quantity of water leaking through the hole is small compared to the normal output of the pump. Finally the comparison between normal and leakhole piston pump and the effect of this leakhole on the cavitation phenomena are studied

Nonlinear dynamic modeling and fluid–mechanism interaction analysis of reciprocating pump–pipeline system

The dynamic characteristics of reciprocating pump–pipeline system are directly affected by the fluid–mechanism dynamic interaction related to the slider-crank mechanism, valves and pipes conveying fluid. In this article, the fluid–mechanism interaction and nonlinearities involved in the kinetic of slider-crank mechanism, the motions of pump valves and the dynamic transmission in pipeline are explored for the nonlinear dynamic modeling of reciprocating pump–pipeline interaction systems. The nonlinear fluid–mechanism coupling model and corresponding analysis procedure are presented for investigating the system dynamic characteristics at all operating conditions. An experiment platform consisting of a simplex plunger reciprocating pump and suction and discharge pipes with a flow control valve is established to validate the proposed model. By the comparisons of pressure pulsations under multi-working conditions, the results obtained from the proposed model show good agreement with the test data. The dynamic characteristic of pump, as well as the effects of interaction and nonlinearity on the flow pulsation, are studied with the proposed model. It is found that nonlinear factors such as joint clearance and nonlinear spring stiffness are of great importance to the lag characteristics of pump valves and the pressure pulsation of pump–pipe system. The amplitudes of pressure pulsation increase with the decrease of control valve opening nonlinearly, and the effect of flow control valve becomes significant when the opening is less than 40%.