Computational Fluid Dynamics Investigation of Turbulent Flow Inside a Rotary Double External Gear Pump

2014 ◽  
Vol 137 (2) ◽  
Author(s):  
Jafar Ghazanfarian ◽  
D. Ghanbari
Keyword(s):  
Turbulent Flow ◽  
Flow Rate ◽  
Volume Fraction ◽  
Complex Geometry ◽  
Volumetric Flow Rate ◽  
Gear Pump ◽  
Linear Behavior ◽  
Rate Characteristic ◽  
Flow Rate Characteristic ◽  
External Gear Pump

This article presents a numerical investigation of 2D turbulent flow within a double external gear pump. The configuration of the inlet and outlet ports is determined such that the double gear pump acts like the combination of two parallel pumps. The complex geometry of the double gear pump, existence of narrow gaps between rotating and stationary walls, and rapidly deforming flow domain make the numerical solution more complicated. In order to solve the mass, momentum, and energy conservation laws along with the k-ε turbulence model, a second-order finite volume method has been used over a dynamically varying unstructured mesh. The numerical results including pressure contours, velocity vectors, flow patterns inside the suction chamber, leakage paths, and time variation of volumetric flow rate are presented in detail. The flow rate characteristic curves with linear behavior are demonstrated at rotational speeds and outlet pressures in the range of 1500–4000 rpm and 2–80 bar, respectively. The effect of reducing the gear-casing gap-size on the augmentation of the net flow rate has been investigated. It is concluded that the minimum oil pressure within the gear pump occurs at the two places between contacting gears near the inlet ports. The contours of vapor volume fraction are also illustrated.

scholarly journals Turbine Dimensionless Coefficients and the Net Head/Flow Rate Characteristic for a Simplified Pico Hydro Power System

2018 ◽  
pp. 1-17
Author(s):  
Alex Okibe Edeoja ◽  
Matthew Ekoja ◽  
Joshua Sunday Ibrahim
Keyword(s):  
Flow Rate ◽  
Standard Procedure ◽  
Volumetric Flow Rate ◽  
Operational Parameters ◽  
Hydro Power ◽  
Hydraulic Machines ◽  
Rate Characteristic ◽  
Shaft Power ◽  
Turbine Shaft ◽  
Flow Rate Characteristic

The basic operational parameters of a simplified pico-hydropower system with provision for water recycling were investigated. Five simplified turbine of runner diameters 0.45, 0.40, 0.35, 0.30 and 0.25 m were designed, locally fabricated, and tested in conjunction with five PVC pipes of diameters 0.0762, 0.0635, 0.0508, 0.0445 and 0.0381 m as penstocks. Five simple nozzles of area ratios 1.0, 0.8, 0.6, 0.4 and 0.2 were fabricated for each penstock diameter. The turbines were successively mounted at the foot of an overhead reservoir such that the effective vertical height from the outlet of the reservoir to the plane of the turbine shaft was 6.95 m. A 1.11 kW electric pump was used to recycle the water downstream of the turbine back to the overhead reservoir. The mean maximum and minimum rotational speeds of the shaft of each turbine were measured for each penstock diameter and nozzle area ratio, and the volumes of water displaced in the reservoirs were also monitored. These measured data were used to compute shaft power and system volumetric flow rate for each operation. Dimensionless flow, head and power coefficients, and specific speed were computed and functional characteristics relating them developed. This standard procedure generally used for the analysis of geometrically similar hydraulic machines have been applied to this system and the results obtained will be invaluable in development of the system into a simple, environmentally friendly and decentralized small power generation system that could potentially contribute positively to the energy mix in Nigeria. The possibility of scaling the system to accommodate larger turbine and penstock diameters, and as a result higher capacity alternators exist and is a target for future developments.

Experimental Investigation of Flowrate Irregularity in Rotary Gear Pumps

1992 ◽  
Author(s):  
G. Mimmi
Keyword(s):  
Experimental Investigation ◽  
Flow Rate ◽  
Experimental Tests ◽  
Periodic Variation ◽  
Experimental Results ◽  
Gear Pump ◽  
Gear Pumps ◽  
Hot Film ◽  
Instantaneous Flow Rate ◽  
External Gear Pump

Abstract In a previous paper the author proposed a method to reduce the periodic variation in flow rate for an external gear pump. To verify the experimental results, a series of experimental tests on a expressly realized gear pump, was carried out. The pump was equipped with relieving grooves milled into the side plates. The tests were done on a closed piping specifically realized and equipped for measuring the instantaneous flow rate of the fluid through a wedge-shaped hot film probe.

scholarly journals CFD Modelling of Global Mixing Parameters in a Peirce-Smith Converter with Comparison to Physical Modelling

2011 ◽  
Vol 6 (1) ◽  
Author(s):  
Deside K Chibwe ◽  
Guven Akdogan ◽  
Chris Aldrich ◽  
Rauf H Eric
Keyword(s):  
Flow Rate ◽  
Volume Fraction ◽  
Mixing Time ◽  
Volumetric Flow Rate ◽  
Numerical Code ◽  
Mixing Efficiency ◽  
Phase System ◽  
Cfd Modelling ◽  
Cold Model ◽  
Peirce Smith Converter

The flow pattern and mixing in an industrial Peirce-Smith converter (PSC) has been experimentally and numerically studied using cold model simulations. The effects of air volumetric flow rate and presence of overlaying slag phase on matte on the flow structure and mixing were investigated. The 2-D and 3-D simulations of the three phase system were carried out using volume of fluid (VOF) and realizable k - ɛ turbulence model to account for the multiphase and turbulence nature of the flow respectively. These models were implemented using commercial Computational Fluid Dynamics (CFD) numerical code FLUENT. The cold model for physical simulations was a 1:5 horizontal cylindrical container made of Perspex with seven tuyeres on one side of the cylinder typifying a Peirce-Smith converter. Compressed air was blown into the cylinder through the tuyeres, simulating air or oxygen enriched air injection into the PSC. The matte and slag phases were simulated with water and kerosene respectively in this study. The influence of varying blowing conditions and simulated slag quantities on the bulk mixing was studied with five different air volumetric flow rates and five levels of simulated slag thickness. Mixing time results were evaluated in terms of total specific mixing power and two mixing time correlations were proposed for estimating mixing times in the model of PSC for low slag and high slag volumes. Both numerical and experimental simulations were in good agreement to predict the variation characteristics of the system in relation to global flow field variables set up in the converter through mathematical calculation of relevant integrated quantities of turbulence, Volume Fraction (VF) and velocity magnitudes. The findings revealed that both air volumetric flow rate and presence of the overlaying slag layer have profound effects on the mixing efficiency of the converter.

scholarly journals Flow Characteristic and Trapping Characteristics of Cycloid Rotor Pump

2015 ◽  
Vol 9 (1) ◽  
pp. 449-454 ◽  
Author(s):  
Ren Zhenxing ◽  
Liu Chunyan ◽  
Li Yulong
Keyword(s):  
Flow Rate ◽  
Flow Characteristics ◽  
Position Angle ◽  
Gear Pump ◽  
Rotary Pump ◽  
Uniformity Coefficient ◽  
Discharge Pressure ◽  
Instantaneous Flow Rate ◽  
External Gear Pump ◽  
Better Than

To accurately calculate the flow rate of cycloid rotary pump as well as to correctly understand its trapped oil phenomenon, firstly the instantaneous flow rate formula of cycloid rotary pump was established based on the method of swept area, and then it was compared with the two present approximate formulas by an example. Secondly, based on the established flow rate formula and the created trapped oil model in the present literature, the trapped oil pressure of a single cavity near the minimum volume position was simulated. It was pointed that for cycloid rotary pump as an example, the flow non-uniform coefficient was 6.45%, and in contrast, the flow non-uniformity coefficient of external gear pump was 21.2%. Relative to the accurate results, the two present approximate errors of flow rates were 1.93% and 2.90%; and the present approximate error of flow non-uniform coefficient was 7.13%; when the minimum position angle was added by 0.5° or 1° or 2°, relative to discharge pressure of the pump, the corresponding maximum peak of trapped oil pressure increased by 1.6% or 6.0% or 21.7%. The results indicate that the flow characteristics of cycloid rotary pump are better than the external gear pump, the two present approximate errors of flow rate are little but the present approximate error of flow non-uniform coefficient is higher. Also, there is a trapped oil phenomenon in cycloid rotary pump which is not obvious.

Determination of Flow Rate Characteristics for Pneumatic Components During Isothermal Discharge by Integral Algorithm

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Tao Wang ◽  
Ling Zhao ◽  
Tong Zhao ◽  
Wei Fan ◽  
Toshiharu Kagawa
Keyword(s):  
Flow Rate ◽  
Pressure Sensors ◽  
Pressure Response ◽  
Experimental Result ◽  
Rate Characteristic ◽  
Flow Rate Characteristic ◽  
Discharge Method ◽  
Measured Pressure ◽  
Error Method

In this paper, we proposed a method to determine the flow rate characteristic parameters directly by using an integral algorithm which is not needed to calculate the flow rate. In the isothermal discharge method discussed by ISO, the flow rate characteristics of pneumatic components can be obtained by pressure response and flow rate. The pressure response is measured in an isothermal tank and the flow rate can be given by differentiating the measured pressure response. Because of using the differential algorithm, calculation precision for measurement error and distribution is much poorer. By integrating pressure experimental result with least error method, characteristics can be obtained easily with Excel tool. Some experimental results are given to show that the proposed calculation method in this paper is more effective than the conversational method by using pressure sensors with different precision.

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