Rotodynamic pumps. Forces and moments on flanges. Centrifugal, mixed flow and axial flow horizontal and vertical shafts pumps

2009 ◽  
Keyword(s):  
Author(s):  
S Sarkar

The results presented here are part of a detailed programme measuring the aerodynamics of a high specific speed mixed flow pump impeller over a wide range of operating conditions, including its behaviour in the unsteady stalled regime. The aim is to elucidate the physics of the flow through such an impeller. The noticeable features are the formation of part-span rotating stall cells having no periodicity and organized structure at reduced flow and also the shifting positions of reversal flow pockets as the flowrate changes. Measurements of loss and its variation with span-wise positions and flowrates enable the variation of local efficiency to be determined. The overall flow picture is similar to that expected in an axial flow impeller, though the present impeller displays a narrow stall hysteresis loop almost right through its operating range.


1998 ◽  
Vol 22 (5) ◽  
pp. 366-370 ◽  
Author(s):  
Kenji Araki ◽  
Hirofumi Anai ◽  
Mitsuo Oshikawa ◽  
Kunihide Nakamura ◽  
Toshio Onitsuka

2012 ◽  
Vol 15 (3) ◽  
pp. 032050
Author(s):  
L Cheng ◽  
C Liu ◽  
C Luo ◽  
J R Zhou ◽  
Y Jin

Author(s):  
Michael Casey ◽  
Christof Zwyssig ◽  
Chris Robinson

The specific speed and specific diameter of radial, mixed and axial flow compressors can be plotted in a Cordier diagram, and the best compressors then lie in a relatively narrow band, known as the Cordier or Balje line. This line exhibits a distinctive s-shape, and it is shown in this paper that this is due to the variation of the centrifugal effect on the pressure rise of the different compressor types. A new equation for the Cordier line in the mixed flow region based on the pressure rise coefficient is developed and calibrated with data from mixed flow pumps and ventilators. Together with other empirical relationships for the expected efficiency as a function of the specific speed this provides some useful new guidelines for the preliminary design of mixed flow compressors. These guidelines are then examined by carrying out a preliminary design of a high-speed mixed-flow micro-compressor that is analyzed using CFD and tested to justify the approach.


2000 ◽  
Vol 122 (2) ◽  
pp. 345-348 ◽  
Author(s):  
Steven M. Miner

This paper presents the results of a study using coarse grids to analyze the flow in the impellers of an axial flow pump and a mixed flow pump. A commercial CFD code (FLOTRAN) is used to solve the 3-D Reynolds Averaged Navier Stokes equations in a rotating cylindrical coordinate system. The standard k−ε turbulence model is used. The meshes for this study use 22,000 nodes and 40,000 nodes for the axial flow impeller, and 26,000 nodes for the mixed flow impeller. Both models are run on a SPARCstation 20. This is in contrast to typical analyses using in excess of 100,000 nodes. The smaller mesh size has advantages in the design environment. Stage design parameters for the axial flow impeller are, rotational speed 870 rpm, flow coefficient ϕ=0.13, head coefficient ψ=0.06, and specific speed 2.97 (8101 US). For the mixed flow impeller the parameters are, rotational speed 890 rpm, flow coefficient ϕ=0.116, head coefficient ψ=0.094, and specific speed 2.01 (5475 US). Evaluation of the models is based on a comparison of circumferentially averaged results to measured data for the same impeller. Comparisons to measured data include axial and tangential velocities, static pressure, and total pressure. A comparison between the coarse and fine meshes for the axial flow impeller is included. Results of this study show that the computational results closely match the shapes and magnitudes of the measured profiles, indicating that coarse CFD models can be used to accurately predict performance. [S0098-2202(00)02202-1]


2012 ◽  
Vol 576 ◽  
pp. 154-161
Author(s):  
Nabeel Adeyemi ◽  
A.K.M. Mohiuddin ◽  
Muhamad Husaini ◽  
Ahmad Tariq Jameel

In recent times, impellers have been designed and modified to combine unique hydrodynamic features to overcome redundancy during mixing. One of such impeller is the mixed-flow impeller which displays a unique combination of radial and axial flow. In this paper, the flow characteristic of a mixed-flow impeller is reported. The main focus is to compare the axial and radial characteristic of the velocity component using experimental and numerical study. The continuity and momentum equation were solved using the Reynold’s stress model (RSM). The field of view away from and below the impeller compared better with the numerical solution for the mean, radial and axial velocity component. Although the RSM was used at a higher computational cost, associated power number and energy of the impeller was also observed to be better predicted.


1998 ◽  
Vol 18 (Supplement1) ◽  
pp. 37-40
Author(s):  
Kota SHIMADA ◽  
Hisao HAGIWARA ◽  
Taiji SAKAI ◽  
Koichi OHYAMA

Author(s):  
Samuel P Lee ◽  
Martyn L Jupp ◽  
Simon M Barrans ◽  
Ambrose K Nickson

Current trends in the automotive industry towards engine downsizing means turbocharging now plays a vital role in engine performance. A turbocharger increases charge air density using a turbine to extract waste energy from the exhaust gas to drive a compressor. Most turbocharger applications employ a radial inflow turbine. However, to ensure radial stacking of the blade fibers and avoid excessive blade stresses, the inlet blade angle must remain at zero degrees, creating large incidence angles. Alternately, mixed flow turbines can offer non-zero blade angles while maintaining radial stacking of the blade fibers and reducing leading edge separation at low velocity ratios. Furthermore, the physical blade cone angle introduced reduces the blade mass at the rotor outer diameter reducing rotor inertia and improving turbine transient response. The current paper investigates the performance of a mixed flow turbine under a range of pulsating inlet flow conditions. A significant variation in incidence across the LE span was observed within the pulse, where the distribution of incidence over the LE span was also found to change over the duration of the pulse. Analysis of the secondary flow structures developing within the volute shows the non-uniform flow distribution at the volute outlet is the result of the Dean effect in the housing passage. In-depth analysis of the mixed flow effect is also included, showing that poor axial flow turning ahead of the rotor was evident, particularly at the hub, resulting in modest blade angles. This work shows that the complex secondary flow structures that develop in the turbine volute are heavily influenced by the inlet pulsating flow. In turn, this significantly impacts the rotor inlet conditions and rotor losses.


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