Jet pump with variable area ratio

Abstract

The invention relates to a jet pump with a variable area ratio. The jet pump with the variable area ratio comprises a water inlet pipe, a water suction pipe, a suction chamber, a throat pipe and a diffusing pipe. A nozzle is mounted at the tail end of the water inlet pipe and located in the suction chamber. The jet pump is characterized in that the nozzle is a nozzle with a cross-section-changeable outlet; the nozzle with the cross-section-changeable outlet comprises an elastic plastic piece, an elastic runner, a threaded boss and a threaded locking ring; the threaded locking ring and the threaded boss are connected through threads and arranged on the outer surface of the elastic plastic piece in a sleeving mode; the opening degree of the elastic plastic piece is changed by rotating the threaded locking ring to change the axial displacement controlling the threaded locking ring; the elastic runner shrinks or expands under extrusion of the elastic plastic piece to change the sectional area of the outlet of the nozzle, so the area ratio of the jet pump can be changed on the premise that the nozzle is not replaced and an internal flow field of the nozzle is not influenced.

Description

technical field [0001] The invention relates to a jet pump with variable area ratio. The invention relates to a jet pump whose area ratio can be changed without affecting the flow channel by adjusting the contraction angle of the nozzle of the jet pump. Background technique [0002] The jet pump uses liquid as the working medium, and through the turbulent diffusion of fluid particles, it transfers energy to a fluid mechanical device to be pumped; the jet pump is composed of a nozzle, a throat, a suction chamber and a diffusion tube; the throat and The nozzle area ratio is the most important size parameter of the jet pump, which directly affects the performance of the jet pump; when the ratio of the throat area of ​​a jet pump to the nozzle area is fixed, and the other dimensions change within a certain range, the change of the performance curve of the jet pump will be affected. limited. [0003] However, it is difficult for the jet pump to work stably in the high-efficiency...

AI Technical Summary

Problems solved by technology

[0003] However, it is difficult for the jet pump to work stably in the high-efficiency area when it is working. Changes in the head flow of the working hydraulic power source and the water level of the suction liquid will cause the jet pump to deviate from the original working point; and the jet pump is often designed according to the supporting power machine. , if it is used alone or with other power machines, it is difficult for the jet pump to operate in the design working area, which not only greatly reduces the efficiency of the jet pump, but also easily causes cavitation; therefore, the jet pump with a fixed area ratio has a large In order to meet the needs of different workplaces, replacing a new jet pump is not only time-consuming and laborious, but also will greatly increase the cost of use

[0004] Therefore, it is of great practical significance to develop a jet pump with a variable area ratio. At present, most of the existing variable jet pumps are adjustable annular jet pumps (201310141547.9), which consist of rectifying components, mixing tubes, throats, and diffuser tubes. , the outlet pipes are connected in turn, the rectifier pipe is connected with the working fluid pipe, and the rectifier pipe is provided with an end cover at one end. However, the annular jet has a large jet loss relative to the center jet pump, and its structure is suitable for the transportation of solid particles such as minerals, live fish, capsules, potatoes and onions; while the existing center jet pump with variable area ratio (90109386.6 , 201020526369.3) are achieved by replacing the nozzle, the nozzle is threaded through the boss on the jet pump body and the jet pump body, and the nozzle is replaced through the threaded connection, thereby achieving the purpose of adjusting the area ratio, not only requires additional nozzles to provide a variety of The required area ratio, and the pump must be stopped every time to disassemble and replace, which is time-consuming and laborious; irrigation and drainage machinery "Numerical Simulation of Adjustable Jet Pump Performance" (No. 6, 2008) proposed a thimble type variable area ratio jet pump. The working principle is to change the flow area of ​​the nozzle by adjusting the thimble installed behind the nozzle concentric with the nozzle to adjust the area of ​​the jet pump; however, because the thimble occupies the center flow channel of the jet pump, the working fluid flow channel forms a ring , which destroys the flow field in the core area of ​​the jet, not only causing resistance loss, but also disturbing the jet flow field, which affects the normal operation of the jet pump

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