Analysis, Design and Validation of a Vaned Diffuser for Improved Fish Friendliness

2021 ◽  
Author(s):  
Qiang Pan ◽  
Weidong Shi ◽  
ZHANG Desheng ◽  
Bart van Esch
Keyword(s):  
Great Improvement ◽  
Rotor Blades ◽  
Peak Efficiency ◽  
Mixed Flow ◽  
Pump System ◽  
Vaned Diffuser ◽  
Pump Performance ◽  
Pump Head ◽  
Analysis Design ◽  
Specific Speed

Abstract The primary cause of mechanical-related fish injury and mortality in turbomachinery is blade strike. Fish contained in the flow may strike with the rotor blades and the fixed diffuser vanes, the latter being a non-negligible factor causing fish damage in pump system. In this study, an experiment-based correlation of fish mutilation ratio acts as critical strike velocity. The relation between strike damage in a vaned diffuser and the theoretical pump head is presented as a function of specific speed. As an example, a vaned diffuser is designed for a single-bladed, mixed-flow impeller with the purpose of improving fish friendliness. This pump can be scaled to operate with a head up to 14 m at peak efficiency, without fish damage in the diffuser. Subsequently, experiments are conducted to show the retained pump performance as well as the great improvement of fish friendliness.

A Study of Tip Clearance Effect for a Mixed-Flow Pump on Performance

2013 ◽  
Author(s):  
Dong Jun Kim ◽  
Young Uk Min ◽  
Jin Young Kim ◽  
Kyung Nam Chung
Keyword(s):  
Power Plants ◽  
Performance Test ◽  
High Efficiency ◽  
Tip Clearance ◽  
Hydraulic Efficiency ◽  
Mixed Flow ◽  
Pump Head ◽  
Specific Speed ◽  
Desalination Plants ◽  
Flow Pump

A vertical mixed-flow pump characterized as large flowrate and high efficiency is used for water supply in the power plants and seawater desalination plants. High specific speed pumps, like axial and mixed-flow pumps, tend to present saddled formation “dip” which restricts the operation range of the pumps due to vibration and noise. In this study, the pump performance test was performed to compare with the numerically simulated results for the mixed-flow pump with specific speed of 780 (m3/min, m, rpm). The impeller tip clearance effect on the pump head and hydraulic efficiency was investigated. The numerically simulated results showed that tip clearance effect changes Q-H curve. It is deduced that altered flow field of outer streamline is related with the prediction of dip phenomenon. Also, possible causes of dip were investigated and a new pump having Q-H curve free from saddled formation was designed.

scholarly journals Prediction and Evaluation of Waterjet Pump Performance under Nonuniform Inflow Using Parallel Compressor Theory

Water ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 99
Author(s):  
Puyu Cao ◽  
Rui Zhu
Keyword(s):  
Flow Instability ◽  
Internal Flow ◽  
Weighted Sum ◽  
Pump Performance ◽  
Inlet Velocity ◽  
Inlet Distortion ◽  
Pump Head ◽  
Compressor Performance ◽  
Waterjet Pump ◽  
External Characteristics

Parallel compressor theory (PCT) is commonly used to estimate effects of inlet distortion on compressor performance. As well as compressor, the actual inflow to pump is also nonuniform and unfavorable for performances. Nowadays, insufficient understanding of nonuniform inflow effects on pump performance restricts its development. Therefore, this paper applies PCT to predict external characteristics and evaluate internal flow instability of waterjet pump under nonuniform inflow. According to features of nonuniform inflow, the traditional PCT is modified and makes waterjet pump sub-divided into two circumferential tubes owning same performances but with different inlet velocity (representing nonuniform inflow). Above all, numerical simulation has been conducted to validated the applicability and accuracy of PCT in head prediction of waterjet pump under nonuniform inflow, since area-weighted sum of each tube head (i.e., theoretical pump head) is highly consistent with simulated result. Moreover, based on identifications of when and which tube occurs stall, PCT evaluates four stall behaviors of waterjet pump: partial deep stall, partial stall, pre-stall and full stall. Furthermore, different stall behavior generates different interactions between head variation of each tube, resulting in a multi-segment head curve under nonuniform inflow. The modified PCT with associated physical interpretations are expected to provide a sufficient understanding of nonuniform inflow effects on pump performances.

Pump Performance Improvement by Restraining Back Flow in Screw-Type Centrifugal Pump

2005 ◽  
Vol 127 (4) ◽  
pp. 755-762 ◽  
Author(s):  
Yasushi Tatebayashi ◽  
Kazuhiro Tanaka ◽  
Toshio Kobayashi
Keyword(s):  
Pressure Fluctuations ◽  
Centrifugal Pumps ◽  
Two Phase ◽  
Simple Method ◽  
Back Flow ◽  
Pump Performance ◽  
Impeller Outlet ◽  
Pump Head ◽  
The Difference ◽  
Set Up

The authors have been investigating the various characteristics of screw-type centrifugal pumps, such as pressure fluctuations in impellers, flow patterns in volute casings, and pump performance in air-water two-phase flow conditions. During these investigations, numerical results of our investigations made it clear that three back flow regions existed in this type of pump. Among these, the back flow from the volute casing toward the impeller outlet was the most influential on the pump performance. Thus the most important factor to achieve higher pump performance was to reduce the influence of this back flow. One simple method was proposed to obtain the restraint of back flow and so as to improve the pump performance. This method was to set up a ringlike wall at the suction cover casing between the impeller outlet and the volute casing. Its effects on the flow pattern and the pump performance have been discussed and clarified to compare the calculated results with experimental results done under two conditions, namely, one with and one without this ring-type wall. The influence of wall’s height on the pump head was investigated by numerical simulations. In addition, the difference due to the wall’s effect was clarified to compare its effects on two kinds of volute casing. From the results obtained it can be said that restraining the back flow of such pumps was very important to achieve higher pump performance. Furthermore, another method was suggested to restrain back flow effectively. This method was to attach a wall at the trailing edge of impeller. This method was very useful for avoiding the congestion of solids because this wall was smaller than that used in the first method. The influence of these factors on the pump performance was also discussed by comparing simulated calculations with actual experiments.

3D Flow Simulation of a Twin-Screw Pump for the Analysis of Gap Flow Characteristics

2021 ◽  
Author(s):  
Ali Hassannejadmoghaddam ◽  
Boris Kutschelis ◽  
Frank Holz ◽  
Tomas Börjesson ◽  
Romuald Skoda
Keyword(s):  
Flow Rate ◽  
Volume Flow Rate ◽  
Overset Grid ◽  
3D Flow ◽  
Screw Pump ◽  
Pump Performance ◽  
Gap Flow ◽  
Wide Range ◽  
Twin Screw ◽  
Pump Head

Abstract Unsteady 3D flow simulations on a twin-screw pump are performed for an assessment of the radial, circumferential and flank gap flow effect on the pump performance. By means of the overset grid technique rigid computational grids around the counter-rotating spindles yield a high cell quality and a high spatial resolution of the gap backflow down to the viscous sublayer in terms of y^+ < 1 . An optimization of the hole-cutting process is performed on a generic gap flow and transferred to the complex moving gaps in the pump. Grid independence is ensured, and conservation properties of the overset grid interpolation technique are assessed. Simulation results are validated against measured pump characteristics. Pump performance in terms of pressure build-up along the flow path through the spindles and volume flow rate is presented for a wide range of spindle speed and pump head. Flow rate fluctuations are found to depend on head but hardly on speed. By a profound assessment of the respective radial, circumferential and flank gap contribution to the total backflow, the importance of the most complex flank gap is pointed out. Backflow rate characteristics in dependence on the pump head and the pump speed are presented.

scholarly journals ANALISA PERHITUNGAN DAYA POMPA SENTRIFUGAL DI GEDUNG UNIVERSITAS 17AGUSTUS 1945 JAKARTA

2019 ◽  
Vol 4 (1) ◽  
pp. 7-14
Author(s):  
M Fajri Hidayat ◽  
Nor Fajri
Keyword(s):  
Pump Power ◽  
Centrifugal Pump ◽  
Water Requirement ◽  
Clean Water ◽  
Pump Head ◽  
Pump Shaft ◽  
Specific Speed

AbstrakPompa adalah suatu alat atau mesin untuk memindahkan cairan dari satu tempat ketempat lain melalui suatu media perpipaan dengan cara menambahkan energi pada cairan yang dipindahkan dan berlangsung secara terus menerus. Pompa yang digunakan dalam analisa ini yaitu Pompa Sentrifugal yang terdapat di gedung Universitas 17 Agustus 1945 Jakarta. Tujuan dari analisa ini yaitu untuk mengetahui kebutuhan air pada gedung Universitas 17 Agustus 1945 Jakarta. Kebutuhan air pada gedung Universitas 17 Agustus 1945 Jakarta dihitung berdasarkan luas lantai gedung dan pemakaian setiap dosen, karyawan, mahasiswa, dan rektorat di Universitas 17 Agustus 1945 Jakarta. Hasil analisa di dapatkan total kebutuhan air bersih pada gedung Universitas 17 Agustus 1945 Jakarta adalah 1.7910 Liter/hari. Kapasitas pompa sebesar 0.06 m3/s. Head total pompa sebesar 31.99 m. Putaran poros pompa yaitu 1500 rpm. Daya pompa sebesar 0.817 kW. Kecepatan spesifik sebesar 48.51 rpm. Dari hasil analisa dapat dinyatakan bahwa Pompa Sentrifugal yang berada di gedung Universitas 17 Agustus 1945 Jakarta sudah layak untuk digunakan. Kata Kunci : Kebutuhan air, kapasitas pompa, pompa sentrifugal Abstract          A pump is a device or a machine to move liquids from one place to another via a piping medium by adding energy to the fluid that is moved and continuous. The pump used in this analysis is the Centrifugal Pump contained in the building University 17 August 1945 Jakarta. The purpose of this analysis is to determine the needs of water in the building University 17 August 1945 Jakarta. Water requirement at University building August 17, 1945 Jakarta is calculated based on building floor and usage of every lecturer, staff, student, and rectorate in University 17 August 1945 Jakarta. The result of the analysis in obtaining the total clean water requirement at the building University 17 August 1945 Jakarta is 1.7910 Liter / day. The pump capacity is 0.06 m3 / s. The total pump head is 31.99 m. The rotation of the pump shaft is 1500 rpm. The pump power is 0.817 kW. Specific speed of 48.51 rpm. The results of the analysis can be stated that the Centrifugal Pump located in the building University 17 August 1945 Jakarta is feasible to use. Keywords : Water requirement, pump capacity, centrifugal pump

Pump Performance Improvement by Restraining Back Flow in Screw-Type Centrifugal Pump

2005 ◽  
Author(s):  
Yasushi Tatebayashi ◽  
Kazuhiro Tanaka ◽  
Toshio Kobayashi
Keyword(s):  
Pressure Fluctuations ◽  
Centrifugal Pumps ◽  
Two Phase ◽  
Simple Method ◽  
Back Flow ◽  
Pump Performance ◽  
Impeller Outlet ◽  
Pump Head ◽  
The Difference ◽  
Set Up

The authors have been investigating the various characteristics of screw-type centrifugal pumps, such as pressure fluctuations in impellers, flow patterns in volute casings, and pump performance in air-water two-phase flow conditions. During these investigations, numerical results of our investigations made it clear that three back flow regions existed in this type of pump. Among these, the back flow from the volute casing toward the impeller outlet was the most influential on the pump performance. Thus the most important factor to achieve higher pump performance was to reduce the influence of this back flow. One simple method was proposed to obtain the restraint of back flow and so as to improve the pump performance. This method was to set up a Ring-like wall at the suction cover casing between the impeller outlet and the volute casing. Its effects on the flow pattern and the pump performance have been discussed and clarified to compare the calculated results with experimental results done under two conditions — namely, one with and one without this Ring-type wall. The influence of wall’s height on the pump head was investigated by numerical simulations. In addition, the difference due to the wall’s effect was clarified to compare its effects on two kinds of volute casing. From the results obtained it can be said that restraining the back flow of such pumps was very important to achieve higher pump performance. Furthermore, another method was suggested to restrain back-flow effectively. This method was to attach a wall at the trailing edge of impeller. This method was very useful for avoiding the congestion of solids because this wall was smaller than that used in the first method. The influence of these factors on the pump performance was also discussed by comparing simulated calculations with actual experiments.

A comparative study of the performance of the mixed flow and radial flow variable geometry turbines for an automotive turbocharger

2018 ◽  
Vol 233 (8) ◽  
pp. 2696-2712 ◽  
Author(s):  
K Ramesh ◽  
BVSSS Prasad ◽  
K Sridhara
Keyword(s):  
Mass Flow ◽  
Flow Parameter ◽  
Radial Flow ◽  
Velocity Ratio ◽  
Variable Geometry ◽  
Flow Variable ◽  
Mixed Flow ◽  
Turbine Efficiency ◽  
Variable Geometry Turbine ◽  
Specific Speed

A new design of a mixed flow variable geometry turbine is developed for the turbocharger used in diesel engines having the cylinder capacity from 1.0 to 1.5 L. An equivalent size radial flow variable geometry turbine is considered as the reference for the purpose of bench-marking. For both the radial and mixed flow turbines, turbocharger components are manufactured and a test rig is developed with them to carry out performance analysis. Steady-state turbine experiments are conducted with various openings of the nozzle vanes, turbine speeds, and expansion ratios. Typical performance parameters like turbine mass flow parameter, combined turbine efficiency, velocity ratio, and specific speed are compared for both mixed flow variable geometry turbine and radial flow variable geometry turbine. The typical value of combined turbine efficiency (defined as the product of isentropic efficiency and the mechanical efficiency) of the mixed flow variable geometry turbine is found to be about 25% higher than the radial flow variable geometry turbine at the same mass flow parameter of 1425 kg/s √K/bar m2 at an expansion ratio of 1.5. The velocity ratios at which the maximum combined turbine efficiency occurs are 0.78 and 0.825 for the mixed flow variable geometry turbine and radial flow variable geometry turbine, respectively. The values of turbine specific speed for the mixed flow variable geometry turbine and radial flow variable geometry turbine respectively are 0.88 and 0.73.

An Experimental Study of Rotor-Filter Pump Performance

1982 ◽  
Vol 104 (3) ◽  
pp. 259-268
Author(s):  
K. M. Marshek ◽  
M. R. Naji ◽  
G. C. Andries
Keyword(s):  
Pressure Pulsation ◽  
Flow Characteristics ◽  
Hydraulic Pressure ◽  
Motor Speed ◽  
Rotor Vibration ◽  
Pump Frequency ◽  
Pump System ◽  
Pump Performance ◽  
Filter Pump ◽  
Pulsing Flow

The performance of a rotor-filter pump has been studied experimentally. To develop an understanding of pump performance, and in particular to discern the mechanism of hydraulic pulsing, flow visualization in the rotor, vibration analyses of the pump, frequency analysis of the pump hydraulic pressure pulsation, and analyses of flow characteristics for different pick-up tubes in combination with different impellers and cover plates were conducted. The frequencies of the pump’s hydraulic pulsation is shown to be a function of the number of pick-up arms and the motor speed. The pump vibration and its pulsation amplitude were reduced by increasing the number of pick-up arms or by adding a radial impeller. These actions increased the lowest frequency of pulsation and decreased the chance of excitation of the pump system parts.

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