A liquid jet pump is a type of fluid machinery that does not have rotating parts. It operates by using the entrainment effect of a jet medium and turbulent diffusion to transfer energy from the working fluid to the suction liquid. Due to its simple structure, compact design, excellent sealing performance, and efficient hydraulic transmission, it can be used for long-distance control. This makes it suitable for harsh environments such as high temperature, high pressure, high vacuum, deep water, strong radiation, and corrosive conditions. Today, jet pump technology is widely applied in various fields both domestically and internationally, with its use in plate filters being a notable success.
2. Structural Parameters of Liquid Jet Pumps
2.1 Structure of the Jet Pump
The structural parameters of a jet pump include the area ratio (m), throat length (l2), diffuser length (l4), inlet angle (α1), and diffuser angle (α2). The area ratio is defined as m = F2 / F1 = (d2 / d1)².
The performance of a liquid jet pump is typically described using three key parameters:
- Flow ratio q = Qb / Qa
- Head ratio h = [(HcZc + Vc² / 2g) - (Hb + Zb + Vb² / 2g)] / [(Ha + Za + Va² / 2g) - (Hb + Zb + Vb² / 2g)]
- Efficiency η = qh / (1 - h)
2.2 Influence of Structural Parameters on Performance
According to numerous studies, when the following ranges are used: m = 2–9, l2 = 1–6d0, l4 = 4–9d2, α1 = 15°–120°, α2 = 0°–140°, and v0 < 50 m/s, the jet pump performs effectively.
From these findings, we can see that each parameter has a specific impact:
- The area ratio (m) is the most critical factor, with values between 3–4 yielding the highest efficiency.
- A throat length of l2 = 1.0d0 results in optimal performance.
- The diffuser angle (α2) significantly affects efficiency, with the best range being 40°–100°.
- The inlet angle (α1) has a relatively minor impact on performance.
- The throat length (l4) greatly influences efficiency, with an effective range of 6d2–8d2.
Since experimental results vary depending on the boundary conditions, the influence of each parameter on performance may differ slightly.
3. Testing System for Vacuum Generation by Jet Pump
The jet pump testing system consists of a filter, hydraulic pump, motor, pressure control valve, globe valve, flow meter, jet pump, and vacuum gauge. The components are arranged as follows:
- 1 – Filter
- 2 – Pump
- 3 – Motor
- 4 – Pressure Control Valve
- 5, 8, 10, 12, 13 – Pressure Gauges
- 6, 15 – Shut-off Valves
- 7 – Throttle Valve
- 9, 14 – Flow Meters
- 11 – Jet Pump
- 13 – Vacuum Gauge
4. Test Results and Conclusions
Based on the optimal structural parameters, we selected the following values: m = 3, l2 = 1.0d0, α2 = 80°, l4 = 6d2, and α1 = 120°.
The nozzle diameter was set to d0 = 6 mm, and the test results showed that the developed jet pump could achieve a negative pressure of -0.06 MPa. The vacuum level increased as the pressure difference between the inlet and outlet grew larger.
5. Application of Jet Pump in Plate Filters
Based on the principle of operation, we applied this jet pump in a filtering system. In practical applications, it provided excellent sealing, eliminating any leakage in the entire filtration device. Thus, the use of a jet pump in demanding, leak-free systems proved highly effective, particularly in achieving strong negative pressure sealing.
(Word count: 543)Aluminum Rod,Aluminum Rod Bar,Aluminum Hollow Bar,5052 Aluminum Round Bar
Shandong Great Steel Co.,Ltd , https://www.great-steel.com