CFD-Based Hydraulic Design and Manufacturing of a Multistage Low Specific-Speed Diffuser Pump

2019 ◽  
Author(s):  
Martijn van der Schoot ◽  
Kevin Bruurs ◽  
Eric van der Zijden
Keyword(s):  
Manufacturing Process ◽  
Performance Test ◽  
Guide Vane ◽  
Response Surfaces ◽  
Pump Design ◽  
Simulation Based Design ◽  
Final Design ◽  
Low Specific Speed ◽  
Specific Speed ◽  
Mechanical Pump

Abstract A multistage low specific-speed diffuser pump was designed to achieve very good hydraulic performance with a newly designed integrated diffuser, crossover and return guide vane. The diffuser was designed using a continuous crossover design. The design space of this diffuser was limited because of the usage of a mechanical pump design from a similar existing pump. This paper presents the simulation-based design of this new pump and the role that simulation can play in the manufacturing process. A new diffuser has been designed to obtain optimum efficiency and to ensure that the pump will operate most of its time very close its best efficiency point. The new diffuser was designed using an approach where the diffuser vane was stretched to completely cover the area starting just behind the impeller trailing edge towards the eye of the next stage impeller. This means that the diffuser vanes should now convert velocity into pressure, guide the fluid to the next stage impeller eye while reducing the swirl and uniformizing the flow. The shape of the diffuser has been optimized using response surfaces that were created using Computation Fluid Dynamics (CFD). This way, a diffuser with a minimum amount of losses was obtained, due to smooth and gradual area changes of the waterway. The final design incorporating this diffuser was analyzed using steady-state CFD to create the full performance curve. The design was transferred into a real physical product by manufacturing it. The resulting casting of the diffuser component was scanned using a 3D scanner. The 3D model of the scan was used to make a comparison using CFD between the performance of the designed and the manufactured diffuser. This provided understanding in how deviations due to the manufacturing process influence the performance. Finally, the complete pump underwent a performance test and its results closely matched the performance as calculated using CFD.

Study on Electromagnetic Vibration Pump

2013 ◽  
Vol 774-776 ◽  
pp. 312-315
Author(s):  
Zhan Xiong Lu
Keyword(s):  
Research Field ◽  
Pump Design ◽  
Positive Displacement ◽  
Low Viscosity ◽  
Electromagnetic Vibration ◽  
Displacement Pump ◽  
Small Flow ◽  
Working Principle ◽  
Low Specific Speed ◽  
Specific Speed

Electromagnetic vibration pump is one type of first proposed new household positive displacement pump.It is mainly used to transport water and other low viscosity liquid. It has many advantages including small flow, high head, simple structure,good self-priming performance. Electromagnetic driving method was combined with displacement pump in vibration pump for the first time. Its specific speed can reach below 10,and this is a breakthrough in super-low specific speed pump design. The working principle of electromagnetic vibration pump and its performance were studied in the paper. each of these problems is further discussed and explained in order to point out the research field for the development of electromagnetic vibration pump later.

Shape Optimization of the Pick-Up Tube in a Pitot-Tube Jet Pump

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
J. Meyer ◽  
L. Daróczy ◽  
D. Thévenin
Keyword(s):  
Computer Aided Design ◽  
Characteristic Curve ◽  
Pitot Tube ◽  
Superior Performance ◽  
Jet Pump ◽  
Pump Design ◽  
Standard Design ◽  
Low Specific Speed ◽  
Specific Speed ◽  
The Impact

At a very low specific speed (VLSS), pumps normally suffer from high disk friction losses. In order to solve this issue, it can be helpful to use a different centrifugal pump design, which is not often found in the pump industry: the Pitot-tube jet pump (PTJ pump). It shows superior performance at low specific speed due to a rather unconventional working principle, described in detail in this paper. The key design feature of the PTJ pump is the (fixed) pick-up tube. Its geometry has not varied over the last decades; it is referred to in this study as “initial” or “standard” design configuration. However, optimizing the pick-up tube might lead to a considerably higher performance. Therefore, a parameterized three-dimensional (3D) computer-aided design (CAD) model is used in this study to investigate the impact of shape deformation on pump performance with the help of computational fluid dynamics (CFD). Two CFD approaches are presented and compared for this purpose: a computationally efficient approach with limited accuracy (low-fidelity method) and a more detailed, but computationally more expensive, high-fidelity approach. Using both approaches, it is possible to obtain highly efficient PTJ pumps. As a consequence, first design rules can be derived. Finally, the optimized design has been tested for various operation points, showing that the performance is favorably impacted along the complete characteristic curve.

scholarly journals On the Rotor Stator Interaction Effects of Low Specific Speed Francis Turbines

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Einar Agnalt ◽  
Igor Iliev ◽  
Bjørn W. Solemslie ◽  
Ole G. Dahlhaug
Keyword(s):  
Guide Vane ◽  
Pressure Fluctuations ◽  
Angular Position ◽  
Pressure Sensors ◽  
Pump Turbine ◽  
Blade Loading ◽  
Loading Case ◽  
Rotor Stator Interaction ◽  
Low Specific Speed ◽  
Specific Speed

The rotor stator interaction in a low specific speed Francis model turbine and a pump-turbine is analyzed utilizing pressure sensors in the vaneless space and in the guide vane cascade. The measurements are analyzed relative to the runner angular position by utilizing an absolute encoder mounted on the shaft end. From the literature, the pressure in the analyzed area is known to be a combination of two effects: the rotating runner pressure and the throttling of the guide vane channels. The measured pressure is fitted to a mathematical pressure model to separate the two effects for two different runners. One turbine with 15+15 splitter blades and full-length blades and one pump-turbine with six blades are investigated. The blade loading on the two runners is different, giving different input for the pressure model. The main findings show that the pressure fluctuations in the guide vane cascade are mainly controlled by throttling for the low blade loading case and the rotating runner pressure for the higher blade loading case.

scholarly journals Numerical investigation on the effects of leakage flow from Guide vane-clearance gaps in low specific speed Francis turbines

2020 ◽  
Vol 1608 ◽  
pp. 012016
Author(s):  
Saroj Gautam ◽  
Ram Lama ◽  
Sailesh Chitrakar ◽  
Hari Prasad Neopane ◽  
Biraj Singh Thapa ◽  
...  
Keyword(s):  
Numerical Investigation ◽  
Guide Vane ◽  
Leakage Flow ◽  
Low Specific Speed ◽  
Specific Speed

Investigation of the Flow Instabilities of a Low Specific Speed Pump-Turbine: Part 1 — Experimental and Numerical Analysis

2020 ◽  
Author(s):  
Sabri Deniz ◽  
Armando Del Rio ◽  
Martin von Burg ◽  
Manuel Tiefenthaler
Keyword(s):  
Experimental Data ◽  
Guide Vane ◽  
Turbulence Models ◽  
Operating Mode ◽  
Rotating Stall ◽  
Flow Instabilities ◽  
Pump Turbine ◽  
Flow Features ◽  
Low Specific Speed ◽  
Specific Speed

Abstract This is the first part of a two-part paper focusing on the flow instabilities of low-specific pump turbines. In this part, results of the CFD simulations and experiments of the research carried out on a low specific speed model pump-turbine at HSLU (Lucerne University of Applied Sciences) Switzerland are presented. The requirements of a stable and reliable pump-turbine operation under continuously expanding operating ranges, challenges the hydraulic design and requires new developments. Previous research at the HSLU [1] analyzed the instabilities of a medium specific speed (i.e. nq = 45) pump turbine. This paper presents the results of experimental (model pump-turbine at the test rig) and numerical (CFD) investigations of the pump-turbine instabilities of a low specific speed (nq = 25) pump-turbine in the turbine operating mode in the region of S-shaped characteristics (that is where the pump-turbine is synchronized and oscillations may occur during load rejection). The four-quadrant characteristics of a low specific speed model pump-turbine with two similar runners differentiating in the size (diameter) are measured. Testing of both runners with the same guide vane system provided information about the effects of the increased vaneless space (the distance between the guide vanes and runner) on the pump-turbine performance and stability both in turbine- and pump operating modes. A CFD methodology by using different numerical approaches and applying several turbulence models is developed in order to accurately predicting the characteristics of the reversible pump-turbines in the S-shaped region (speed no load conditions) as well as analyzing the flow features especially at off-design conditions. This CFD model is validated against the experimental data at 6° and 18° guide vane openings in turbine operating mode. With the measured data of the unsteady pressure measurements and detailed investigation of unstable ranges on the pump-turbine characteristics, flow instabilities in the low-specific speed model pump-turbine are analyzed. Relevant frequencies such as rotating stall, steady and unsteady vortex formations are determined. Based on the analysis of the experimental data and CFD results focusing especially on the flow features in the vaneless space and at the runner inlet, the onset and development of the flow instabilities are explored.

Numerical and Experimental Study of Inner Flow and Hydraulic Performance of the Mixed-Flow Pump With Low Specific Speed

2018 ◽  
Author(s):  
Jianping Yuan ◽  
Meng Fan ◽  
Yanjun Li ◽  
Yanxia Fu ◽  
Rong Lu
Keyword(s):  
Rapid Development ◽  
Internal Flow ◽  
Fluctuation Analysis ◽  
Market Demand ◽  
Mixed Flow ◽  
Pump Design ◽  
Flow Rates ◽  
Low Specific Speed ◽  
Specific Speed ◽  
Flow Pump

Mixed flow pumps are very suitable for market demand with the rapid development of urbanization, especially for low specific speed mixed flow pumps which has been widely used in various fields [1–3]. In this study, the calculations of the incompressible 3D internal flow of the mixed-flow pump with low specific speed was carried out by using CFD technique based on the N-S equation coupled with the standard k-ε turbulence model at different flow rates. The hydraulic performances of the mixed-flow pump as well as the inner flow were analyzed in comparison with the corresponding experimental data. Meanwhile, the static pressure and relative velocity distribution on blades were studied at low, design as well as large flow rates, respectively. Finally, it can obtain that the predicted pump performance curves based on numerical simulation have a good agreement with the experimental results, which verify the numerical method applied in this work accurate in a certain extent. Furthermore, the results also provide some references to hydraulic forces and pressure fluctuation analysis and the performance improvement for the mixed-flow pump design.

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