Design and Performance of Vaneless Volutes for Radial Inflow Turbines: Part 1: Non-Dimensional Conceptual Design Considerations

1994 ◽  
Vol 208 (3) ◽  
pp. 199-211 ◽  
Author(s):  
A Whitfield ◽  
A B Mohd Noor
Keyword(s):  
Mach Number ◽  
Swirling Flow ◽  
Flow Direction ◽  
Experimental Studies ◽  
Design Procedure ◽  
Area Ratio ◽  
Working Fluid ◽  
One Dimensional ◽  
The Absolute ◽  
Inlet Conditions

The requirements for the volute of a radial inflow turbine are that it should collect the working fluid, deliver it to the turbine rotor as efficiently as possible and provide the desired rotor inlet conditions. The design requirements of the turbine leads to the rotor design and the identification of the desired flow conditions at rotor inlet in terms of the magnitude and direction of the absolute Mach number. The volute must then be designed to ensure that the desired rotor inlet conditions are attained. A non-dimensional design procedure for a vaneless turbine volute is described. Based on a knowledge of the flow direction and magnitude of the absolute Mach number at rotor inlet the overall dimensions of the volute in terms of the radius ratio and flow area ratio are first established. The overall design is then developed to provide the variation of the volute centroid radius and area ratio with azimuth angle. A trapezoidal cross-sectional shape is then used to establish the outer dimensions of the volute. The non-dimensional procedure assumes a one-dimensional compressible flow and as such relies on the empirical specification of the dissipation of angular momentum, the dissipation of energy and the deviation of the swirling flow from that of a free vortex. The effect of the uncertainties associated with the empirical data on the volute design geometry is assessed. A complementary experimental investigation to develop and substantiate the required empiricism is presented in Part 2, which follows. As the design procedure is essentially one-dimensional it must be interpreted with a knowledge of the actual three-dimensional flow within a volute passage. Supportive experimental studies will be presented in Part 3 in the next issue.

scholarly journals A Non-Dimensional Conceptual Design Procedure for the Vaneless Volutes of Radial Inflow Turbines

1991 ◽  
Author(s):  
A. Whitfield ◽  
A. B. Mohd Noor
Keyword(s):  
Mach Number ◽  
Conceptual Design ◽  
Swirling Flow ◽  
Design Procedure ◽  
Area Ratio ◽  
Working Fluid ◽  
Flow Area ◽  
Cross Sectional ◽  
The Absolute ◽  
Inlet Conditions

The requirements for the volute of a radial inflow turbine are that it should collect the working fluid, deliver it to the turbine rotor as efficiently as possible and provide the desired rotor inlet conditions. The overall performance requirements of the turbine leads to the rotor design and the identification of the desired flow conditions at rotor inlet in terms of the magnitude and direction of the absolute Mach number, see Whitfield (1990). The volute must then be designed to ensure that the desired rotor inlet conditions are attained. A non-dimensional conceptual design procedure for a vaneless turbine volute is described. Based on a knowledge of the magnitude and direction of the absolute Mach number at rotor inlet the overall dimensions of the volute in terms of the radius ratio and flow area ratio are first established. The overall design is then developed to provide the variation of the volute centroid radius and area ratio with azimuth angle. A trapezoidal cross-sectional shape is then used to establish the outer dimensions of the volute. The non-dimensional design procedure assumes a one-dimensional compressible flow and as such relies on the empirical specification of the dissipation of angular momentum, the dissipation of energy, and the deviation of the swirling flow from that of a free vortex. The effect of the uncertainties associated with the empirical data on the volute design geometry is assessed.

Performance Prediction of Twin-Entry Turbocharger Turbines

2002 ◽  
Author(s):  
Shahram Ghasemi ◽  
Ebrahim Shirani ◽  
Ali Hajilouy-Benisi
Keyword(s):  
Performance Prediction ◽  
Flow Direction ◽  
Prediction Method ◽  
One Dimensional ◽  
Plane Normal ◽  
Partial Admission ◽  
Single Entry ◽  
Radial Velocity Profile ◽  
Inlet Conditions ◽  
The One

In this paper, the performance of the twin-entry radial flow turbine under steady state and partial admission conditions is modeled. The method, which is developed here, is based on one-dimensional performance prediction. In one-dimensional modeling, the flow properties are assumed constant on a plane normal to the flow direction. This assumption is in contrast with the flow at the rotor entry of a twin-entry turbine under partial admission condition. In this study the one-dimensional performance prediction method for single-entry turbine is modified to analyze the twin-entry turbine. In particular, the loss coefficients due to friction, clearance and blade loading, which are already developed for single-entry turbines, are modified. Also additional losses in the rotor are considered because of twin-entry rotor inlet conditions and the rotor-mixing losses. Indeed in a single-entry turbine with symmetric volute the flow tends to move toward the shroud. A correlation for the radial velocity profile at the rotor entry for this case is obtained and is considered to be optimum. Then the rotor mixing loss is estimated. Finally a model based on the above mentioned matters is developed. The results obtained from the model are compared with experimental results and good agreements are obtained. In this paper, special behaviors of the flow in the twin-entry turbine are also investigated and some physical interpretations are presented.

scholarly journals Measurementimprovement of flow quality of slotted test section in transonic wind tunnel

2021 ◽  
Vol 39 (3) ◽  
pp. 660-667
Author(s):  
Shenghao Wu ◽  
Jiming Chen ◽  
Qin Chen ◽  
Haitao Pei
Keyword(s):  
Mach Number ◽  
Wind Tunnel ◽  
Test Section ◽  
Experimental Studies ◽  
Flow Characteristics ◽  
Area Ratio ◽  
Straight Section ◽  
Flow Quality ◽  
Transonic Wind Tunnel

Experimental studies were carried out in the 0.6 m×0.6 m continuous transonic wind tunnel of CARDC in order to investigate the flow characteristics of the slotted test section. Experimental results show that the root-mean-square deviation of axial Mach number in the model area is above 0.01 when the test section Mach number is above 1.0.Numerical simulation under the same conditions to investigate the flow characteristics of the slotted section, together with the experimental studies indicate tow phenomena may directly cause the Mach number fluctuation. Firstly, a straight section was installed to connect the nozzle and the test section in the wind tunnel. Weak shock waves due to the curvature discontinuity at the joint of the test section and the straight section contribute to Mach number fluctuation. Secondly, the open-area ratio of both the upper and lower wall of test section, each with 8 slots, is of 10%. The larger porosity leads to stronger expansion waves in the acceleration zone located at the inlet of the test section. The flow was over accelerated because of the stronger expansion wave and thus fluctuate the flow field severely. Two measures were taken to improve the flow quality of the slotted test section based on the above-mentioned analysis: ①Flexible plate instead of solid straight plate was installed to bridge nozzle and test section to eliminate the curvature discontinuity; ②Decreasing the open-area ratio of the upper and lower test section wall to 6% and the number of slots to 6. Numerical and experimental results show that the Mach number fluctuation in the model area was suppressed to a satisfactory degree.

Derivation of Body Force Model Under Ocean Conditions

2017 ◽  
Author(s):  
Yuxian Rao ◽  
Lei Yu
Keyword(s):  
Body Force ◽  
Flow Direction ◽  
The Body ◽  
Working Fluid ◽  
Circulation System ◽  
Ship Motions ◽  
Force Model ◽  
One Dimensional ◽  
Ocean Conditions ◽  
Relap5 Code

The floating nuclear power plant (FNPP) is recently received increasing attention in China. The effects of ship motions on the working fluid of marine-type reactor are not only a change of effective gravity, but also an appearance of additional forces, which requires further researches. This paper focuses on the derivation of body force model under 6 typical ocean conditions. The derived model consists of body force terms based on both three-dimensional and one-dimensional momentum equations and can be applied to the pipe with an arbitrary flow direction. For programming calculation, the integrations with respect to spatial and time variables are performed for the body force terms of one-dimensional momentum equations under 6 typical ocean conditions. For verification purpose, the deprived model is implemented into the RELAP5 code and a two-loop single phase natural circulation system is analyzed using the modified RELAP5 code under 6 typical ocean conditions. The calculation results show that the deprived model is reasonable.

Design and Performance of Vaneless Volutes for Radial Inflow Turbines: Part 2: Experimental Investigation of the Mean Line Performance—Assessment of Empirical Design Parameters

1994 ◽  
Vol 208 (3) ◽  
pp. 213-224 ◽  
Author(s):  
A Whitfield ◽  
S A MacGregor ◽  
A B Mohd Noor
Keyword(s):  
Experimental Investigation ◽  
Static Pressure ◽  
Swirling Flow ◽  
Design Procedure ◽  
Design Parameters ◽  
Flow Angle ◽  
One Dimensional ◽  
Specific Objective ◽  
The Mean ◽  
And Performance

The non-dimensional design procedure described in Part 1 assumed a one-dimensional compressible flow and as such relied on the empirical specification of the dissipation of angular momentum, the dissipation of energy and the deviation of the swirling flow from that of a free vortex. This was based largely on data available in the published literature. In order to develop and substantiate the empirical procedures further an experimental study was carried out in parallel with the development of the design procedure. The experimental investigation described here had the specific objective of assessing and developing appropriate empirical models and coefficients for application to the design procedure. The study concentrated on the application of a five-hole probe located in the centre of the volute passage and at a series of azimuth angles around the discharge. The probe provided stagnation and static pressure measurements, from which the gas velocity was derived, together with the flow angle. When taking measurements at the volute discharge a stationary dummy rotor was used to carry the five-hole probe.

Investigation on the Effects of Various Swirl Generators on Heat Transfer and Fluid Flow in Decaying Swirling Flows

2010 ◽  
Vol 224 (10) ◽  
pp. 2181-2197
Author(s):  
M Ahmadvand ◽  
A F Najafi ◽  
S Shahidinejad
Keyword(s):  
Heat Transfer ◽  
Swirling Flow ◽  
Flow Characteristics ◽  
Axial Flow ◽  
Working Fluid ◽  
Uniform Heat Flux ◽  
Mean Flow ◽  
Inlet Conditions ◽  
The Individual ◽  
Comparison Of The Results

Influences of three typical vortex generators on flow pattern and ensuing heat transfer augmentation were investigated and compared at similar Re and swirl numbers inlet conditions. Studied swirlers such as propeller swirlers, jet-type swirlers, and rotating honeycombs were installed at the pipe inlet. Reynolds number ranges from 10000 to 30000. Swirlers were set on the swirl numbers 1.4, 0.89, and 0.52, which were obtained by propellers. This study has been carried out under uniform heat flux condition and air was employed as the working fluid. The obtained results provide the individual effects of each swirler configuration on mean flow and turbulence distribution as well as on enhancement of heat transfer. Considering S=1.4, jet-type swirlers pointed 133 per cent Nu enhancement compared to axial flow, whereas propellers and rotating honeycombs approached 105 per cent and 79 per cent, respectively. For S=0.89, relative treatment has been changed and propellers with 70 per cent Nu augmentation demonstrated tip-top performance behind of which other swirlers lined. By decreasing the swirl number, approximately closer heat performances were represented from all swirler configurations. Comparison of the results of various swirlers exhibited that Re and swirl numbers are not generally sufficient to determine the swirling flow characteristics and each swirler confirms an individual flow quality.

Performance of a Multiphase Boiling MHD Generator

1981 ◽  
Vol 103 (3) ◽  
pp. 582-586 ◽  
Author(s):  
H. B. Urbach ◽  
J. G. Purnell ◽  
D. T. Knauss
Keyword(s):  
Liquid Metal ◽  
Unit Length ◽  
Working Fluid ◽  
One Dimensional ◽  
Mhd Generator ◽  
Temperature And Pressure ◽  
Inlet Conditions ◽  
Energy Conversion Devices ◽  
Rule Consistency ◽  
Thermodynamic Equations

Adiabatic liquid metal-water MHD generators produce power during water boiling because both temperature and pressure drop throughout the phase change. Therefore, boiling MHD generators with boiling water, as distinguished from purely expansive steam-liquid metal MHD generators, may be useful energy-conversion devices. A generator, with a working fluid consisting of a liquid-metal eutectic of tin and bismuth, water, and steam, was analyzed in accordance with anticipated isentropic efficiencies. Real-gas-law data from steam tables were employed to integrate one-dimensional multiphase thermodynamic equations by using Simpson’s rule. Consistency checks on the boiling section showed errors of about 1 percent. The contribution of the boiling section of the generator was computed to be about 20 percent greater per unit length and 360 percent greater per unit volume than the purely expansive section of the MHD generator for the studied inlet conditions.

Investigation of Tabs in Short Annular Diffusers With Swirling Flow

2015 ◽  
Vol 137 (9) ◽  
Author(s):  
D. J. Cerantola ◽  
A. M. Birk
Keyword(s):  
Cross Section ◽  
Boundary Layer Thickness ◽  
Swirling Flow ◽  
Flow Direction ◽  
Pressure Coefficient ◽  
Area Ratio ◽  
Back Pressure ◽  
Swirl Angle ◽  
Flow Features ◽  
Computational Fluid Dynamics Cfd

Square tabs were placed on the base of an ellipsoidal center-body (CB) in short annular diffusers. Tests were conducted in subsonic swirling flow with an inlet Reynolds number of 1 × 105. The tabs, with a projected height equivalent to the boundary layer thickness, reduced the outlet distortion and incurred a pressure penalty in the three smaller diffusers whose designs were not expected to stall. The largest area ratio (AR = 6.18) diffuser improved back pressure coefficient 4.6% with four tabs that blocked 4.7% of the inlet cross section over its bare diffuser but was 42% lower than that obtained by the AR = 2.73 diffuser with no tabs. Computational fluid dynamics (CFD) was useful for capturing relevant flow features that corroborated with experimental data and literature. Tabs oriented normal to the diffuser axis were less effective at influencing the flow as swirl angle increased but similar elongated wakes oriented with the flow direction were observed at all simulated swirl angles. The CFD either predicted equivalent performance due to the over-prediction associated with diffusion equaling the under-prediction associated with vorticity or over-predicted performance.

scholarly journals Experimental Investigation of the Performance of a Supersonic Compressor Cascade

1988 ◽  
Vol 110 (4) ◽  
pp. 456-466 ◽  
Author(s):  
D. L. Tweedt ◽  
H. A. Schreiber ◽  
H. Starken
Keyword(s):  
Experimental Investigation ◽  
Mach Number ◽  
Flow Direction ◽  
Pressure Ratio ◽  
Density Ratio ◽  
Axial Flow ◽  
Side Wall ◽  
Federal Republic Of Germany ◽  
Compressor Cascade ◽  
Inlet Conditions

Results are presented from an experimental investigation of a linear, supersonic compressor cascade tested in the supersonic cascade wind tunnel facility at the DFVLR in Cologne, Federal Republic of Germany. The cascade was derived from the near-tip section of a high-throughflow axial flow compressor rotor and has a design relative inlet Mach number of 1.61. Test data were obtained over the range of inlet Mach numbers from 1.30 to 1.17. Side-wall boundary layer suction was used to reduce secondary flow effects within the blade passages and to control the axial-velocity-density ratio (AVDR). Flow velocity measurements showing the wave pattern in the entrance region were obtained with a laser anemometer. The unique-incidence relationship for this cascade, relating the supersonic inlet Mach number to the inlet flow direction, is discussed. The influence of static pressure ratio and AVDR on the blade performance is described, and an empirical correlation is used to show the influence of these (independent) parameters for fixed inlet conditions on the exit flow direction and the total-pressure losses.

Optimized Ejector-Diffuser Design Procedure for Natural Gas Vapor Recovery

1983 ◽  
Vol 105 (3) ◽  
pp. 388-393 ◽  
Author(s):  
J. C. Dutton ◽  
B. F. Carroll
Keyword(s):  
High Pressure ◽  
Mach Number ◽  
Natural Gas ◽  
Compression Ratio ◽  
Ambient Pressure ◽  
Design Procedure ◽  
Area Ratio ◽  
Optimized Design ◽  
Storage Tanks ◽  
Oil Storage

A procedure for designing optimized ejector-diffuser systems for recovering natural gas vapor from oil storage tanks is presented. The system utilizes high pressure gas from the separator to entrain the ambient pressure gas from the tanks and then pumps the mixture to the sales line. The analysis predicts the minimum separator pressure and the optimum nozzle Mach number and ejector area ratio required to accomplish this task. The results of a parametric study suggest that this system is feasible and that the higher the required ejector compression ratio the more critical is the use of an optimized design.

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