An Analysis of Flow Through a Mixed Flow Impeller

1972 ◽  
Vol 94 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Yasutoshi Senoo ◽  
Yoshiyuki Nakase
Keyword(s):  
Finite Number ◽  
Flow Condition ◽  
Three Dimensional ◽  
Meridional Plane ◽  
Surfaces Of Revolution ◽  
Mixed Flow ◽  
Numerical Examples ◽  
Orthogonal Coordinate System ◽  
Plane Solution ◽  
Flow Through

In this report, a method of analyzing steady, three-dimensional, subsonic, nonviscous flow through a turbomachine with arbitrary hub and shroud shapes and with a finite number of blades is presented. In order to make the analysis manageable, the stream surfaces are assumed to be axisymmetric. Position and shape of these surfaces, which depend upon the work of blades, are obtained by a meridional plane solution using a quasi-orthogonal coordinate system. The flow condition on these surfaces of revolution and the work of blades are obtained by a new blade-to-blade solution and the results are used to improve the meridional plane solution. This procedure is repeated until solution converges. Some numerical examples are given.

scholarly journals A Quasi-Three Dimensional Analysis of Choking Flow for Radial Gas Turbines

1978 ◽  
Author(s):  
Yoshiyuki Nakase ◽  
Junichiro Fukutomi ◽  
Masanobu Inubushi ◽  
Takashi Watanabe ◽  
Yoshiyasu Hama ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Energy Recovery ◽  
Three Dimensional ◽  
Layer Growth ◽  
Meridional Plane ◽  
Mixed Flow ◽  
Numerical Examples ◽  
Annular Cascade ◽  
Boundary Layer Growth

A quasi-three dimensional.flow analysis has previously been reported for a mixed flow impeller by one of the present authors. In the analysis, the velocity gradient method has been used in meridional plane and the rotating annular cascade theory has been used for blade-to-blade solution. In this report, the analysis is generalized to allow prediction and analysis of choking flow for a radial inflow gas turbine. Moreover, this analysis is corrected to include passage contraction effects and passage loss effects due to boundary-layer growth. The efficiency and choking flow rate of gas turbine may be obtained in a single computer run without the complicated throat area estimation. Some numerical examples for a burst furnace gas energy recovery turbine are presented.

Three-Dimensional Theory of Incompressible and Inviscid Flow Through Mixed Flow Turbomachines

1965 ◽  
Vol 87 (4) ◽  
pp. 361-372
Author(s):  
M. J. Schilhansl
Keyword(s):  
Radial Flow ◽  
Three Dimensional ◽  
Inviscid Flow ◽  
Two Dimensional ◽  
Surfaces Of Revolution ◽  
Dimensional Theory ◽  
Mixed Flow ◽  
Three Dimensional Flow ◽  
Flow Through ◽  
Flow Study

In this paper the author presents a three-dimensional flow study for mixed (axial and radial) flow rotors. In order to make the analysis manageable the actual stream surfaces are assumed to coincide with surfaces of revolution. The intersections of the blade surfaces with these surfaces of revolution are mapped onto planes normal to the axis of the rotor. The investigation of the flow in the “picture” planes is based on available two-dimensional cascade theories. Position and shape of the surfaces depend upon the equilibrium of the flow in the direction perpendicular to the surfaces of revolution. The flow in each individual surface of revolution is found by remapping from the planes. Improved position and shape of the surfaces of revolution can be derived from the equilibrium condition. This procedure must be iterated until two consecutive iterations lead to the same result.

Unsteady Flow at the Outlet of the High Specific Speed Centrifugal Compressor Impeller

1984 ◽  
Author(s):  
Fumikata Kano ◽  
Takafumi Shirakami
Keyword(s):  
Unsteady Flow ◽  
Centrifugal Compressor ◽  
Coal Gasification ◽  
Three Dimensional ◽  
Axial Direction ◽  
Navier Stokes ◽  
Meridional Plane ◽  
Mixed Flow ◽  
Navier Stokes Equation ◽  
Specific Speed

The unsteady flow at the outlet of the high specific speed mixed flow Impeller was studied. The specific speed is 500 (m3/min)1/2 · rpm · m−3/4. The flow is strongly influenced by the impeller blading. The other hand, the flow influences the performance of the stationary vanes downstream of the impeller. The flow path at the outlet of the mixed flow impeller is inclined to the axial direction and is curved in the meridional plane. The study was carried out to develop the 30 MW centrifugal compressor. This compressor is used in the field of the coal gasification, the geothermal power generation, etc. The distributions of flow velocity, pressure and temperature of three dimensional flow were measured using a high sensitive pressure transducer and a total temperature probe. The flow was surveyed across the entire passage at about ten axial locations including endwall boundary layer. A theoretical analysis was also carried out using the linearized Navier-Stokes equation.

Improved κ-ɛ Modelling of Impeller Flow Performance of a Mixed-Flow Pump under off-Design Operating States

1993 ◽  
Vol 207 (4) ◽  
pp. 219-229 ◽  
Author(s):  
S M Fraser ◽  
Y Zhang
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Careful Analysis ◽  
Navier Stokes ◽  
Mean Flow ◽  
Mixed Flow ◽  
Navier Stokes Equations ◽  
Flow Through ◽  
The Mean ◽  
Flow Pump

Three-dimensional turbulent flow through the impeller passage of a model mixed-flow pump has been simulated by solving the Navier-Stokes equations with an improved κ-ɛ model. The standard κ-ɛ model was found to be unsatisfactory for solving the off-design impeller flow and a converged solution could not be obtained at 49 per cent design flowrate. After careful analysis, it was decided to modify the standard κ-ɛ model by including the extra rates of strain due to the acceleration of impeller rotation and geometrical curvature and removing the mathematical ill-posedness between the mean flow turbulence modelling and the logarithmic wall function.

A Study of Flow Behaviour in Radial and Mixed Flow Turbines With Variable Nozzle Vanes for a Turbocharger

2019 ◽  
Author(s):  
Ramesh Kannan ◽  
Bhamidi Prasad ◽  
Sridhara Koppa
Keyword(s):  
Radial Flow ◽  
Expansion Ratio ◽  
Flow Behaviour ◽  
Meridional Plane ◽  
Turbine Stage ◽  
Mixed Flow ◽  
Turbine Wheel ◽  
Flow Through ◽  
Loss Coefficients ◽  
Rotor Loss

Abstract A mixed flow turbine with variable nozzle vanes is developed along with its radial counterpart for the wheel size of about 30 mm, suitable for turbocharger of 1.5 lit. engine capacity. In order to understand the flow behaviour inside the turbines, computational fluid dynamics studies are conducted for both the radial and mixed flow turbines. Flow through the turbine stage is discussed with velocity distribution in the meridional plane. In addition, the loss coefficients for the nozzle vanes and turbine wheel are estimated. At nozzle vanes opening of 50% mass flow parameter and for the turbine expansion ratio of 1.5, the flow velocities at the exit of the nozzle vanes are found to be about 120 to 170 m/s for the radial flow turbine and 150 to 180 m/s for the mixed flow turbine. Higher level of uniformity in flow is also observed for mixed flow turbine stage compared to the radial. The maximum Mach number is observed on the middle of the turbine wheel, and the same is less than unity for both the turbines. Both the nozzle and rotor loss coefficients for mixed flow turbine are lower than the values observed for the radial flow by about 6% and 15% respectively.

Hydraulic Performance of a Mixed-Flow Pump: Unsteady Inviscid Computations and Loss Models

2001 ◽  
Vol 123 (2) ◽  
pp. 256-264 ◽  
Author(s):  
B. P. M. van Esch ◽  
N. P. Kruyt
Keyword(s):  
Potential Flow ◽  
Flow Model ◽  
Three Dimensional ◽  
Hydraulic Performance ◽  
Mixed Flow ◽  
Global Performance ◽  
Flow Through ◽  
Loss Models ◽  
Potential Flow Model ◽  
Flow Pump

The hydraulic performance of an industrial mixed-flow pump is analyzed using a three-dimensional potential flow model to compute the unsteady flow through the entire pump configuration. Subsequently, several additional models that use the potential flow results are employed to assess the losses. Computed head agrees well with experiments in the range 70 percent–130 percent BEP flow rate. Although the boundary layer displacement in the volute is substantial, its effect on global characteristics is negligible. Computations show that a truly unsteady analysis of the complete impeller and volute is necessary to compute even global performance characteristics; an analysis of an isolated impeller channel and volute with an averaging procedure at the interface is inadequate.

A Rim Seal Orifice Model With 2 Cds and Effects of Swirl in Seals

2008 ◽  
Author(s):  
Bruce V. Johnson ◽  
Cheng-Zhang Wang ◽  
Ramendra P. Roy
Keyword(s):  
Experimental Data ◽  
Flow Condition ◽  
Gas Turbines ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Outer Region ◽  
Outer Radius ◽  
Lumped Parameter ◽  
Flow Through ◽  
Two Parameters

Rim seal ingestion models for gas turbines are formulated to estimate the amount of hot fluid ingested through “clearance” seals into the disk cavity. Previous numerical and experimental studies showed the complex time-dependent, three-dimensional characteristics of the flow through the seals and in the outer region of the disk cavity. The present model is developed for estimating ingress and egress flow through the seal that is driven by the azimuthal variation in gas path pressure near the vane and blade platforms. Most published rim seal orifice models have used one “lumped parameter” Cd for both ingress and egress across the seal. However, the flow path from the gas path through the seal is often more convoluted than the flow returning to the gas path. The present Rim Seal Orifice Model includes (i) a Cd value for ingress from the gas path into the disk cavity, (ii) a Cd value for egress from the disk cavity to the gas path and (iii) an estimate for effects of swirl from the seal outer radius to the inner radius of the seal mixing region. The use of two Cd values provides two parameters for characterizing the flow through the seal. The ingress and egress Cd values for a turbine rim seal configuration and flow condition are estimated by comparing the modeled seal effectiveness for a parametric range of ingress and egress Cd values with experimental stator wall measurements. The combination of Cd values, which best matches experimental data over a range of coolant flow ratios, characterizes the seal and flow condition. Arizona State University experimental data were used to estimate the Cd values for an overlap seal configuration.

Experimental and Numerical Study of Three-Dimensional Flows in a Mixed-Flow Pump Stage

1994 ◽  
Author(s):  
T. Takemura ◽  
A. Goto
Keyword(s):  
Numerical Study ◽  
Reverse Flow ◽  
Three Dimensional ◽  
Swirl Flow ◽  
Experimental Results ◽  
Test Fluid ◽  
Internal Flows ◽  
Mixed Flow ◽  
Pump Stage ◽  
Flow Through

Internal flows of a low specific speed pump stage, having a mixed-flow impeller and a vaned bowl diffuser combination, have been investigated experimentally and numerically. Air was used as the test fluid, and the internal flows were measured at various locations and under various capacities. Flow calculations were made, for both the isolated impeller case and the complete stage case, using Denton viscous codes LOSS3D and MULTSTAGE14, by which the three-dimensional steady flow through multiple blade rows can be calculated using the inter-row mixing process. Experimental results showed the effects of the interaction between the impeller and the reverse flow, originating in the downstream diffuser, even at the design point capacity. While an impeller exit reverse flow occurred at the shroud side in the isolated impeller calculation, it was observed at the hub side in the complete stage case, showing good agreement with the experimental results. Although the flow in the diffuser was highly distorted due to a strong swirl flow, patterns of total pressure distribution could be well predicted by the complete stage calculation.

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