An Analysis Method for Multistage Transonic Turbines With Coolant Mass Flow Addition

1998 ◽  
Vol 120 (4) ◽  
pp. 744-752 ◽  
Author(s):  
F. Mildner ◽  
H. E. Gallus
Keyword(s):  
Flow Field ◽  
Mass Flow ◽  
Three Dimensional ◽  
Iterative Solution ◽  
Curvilinear Coordinates ◽  
Main Stream ◽  
Viscous Effects ◽  
Air Mixing ◽  
Volume Method ◽  
Cooling Air

The subject of this paper is a numerical method for the calculation of the transonic flow field of multistage turbines, taking high coolant flow into account. To reduce the processing time, a throughflow method based on the principels of Wu is used for the hub-to-tip calculation. The flow field is obtained by an iterative solution between a three-dimensional inviscid hyperbolic time-dependent algorithm with an implicit finite volume method for the blade-to-blade calculations using C-meshes and a single representative meridional S2m-streamsurface. Along the S2m-plane with respect to nonorthogonal curvilinear coordinates, the stream function equation governing fluid flow is established. The cooling air inflow inside the blade passage forbids the assumption of a constant mass flow along the main stream direction. To consider the change of the aerodynamic and thermodynamic behavior, a cooling air model was developed and implemented in the algorithm, which allows the mixing of radially arbitrarily distributed cooling air in the trailing edge section of each blade row. The viscous effects and the influence of cooling air mixing are considered by the use of selected loss correlations for profile, tip leakage, secondary flow and mixing losses in the S2m-plane in terms of entropy. The method is applied to the four-stage high-temperature gas turbine Siemens KWU V84.3. The numerical results obtained are in good agreement with the experimental data.

scholarly journals An Analysis Method for Multistage Transonic Turbines With Coolant Mass Flow Addition

1997 ◽  
Author(s):  
Frank Mildner ◽  
Heinz E. Gallus
Keyword(s):  
Flow Field ◽  
Mass Flow ◽  
Three Dimensional ◽  
Iterative Solution ◽  
Curvilinear Coordinates ◽  
Main Stream ◽  
Viscous Effects ◽  
Air Mixing ◽  
Orthogonal Curvilinear Coordinates ◽  
Cooling Air

The subject of this paper is a numerical method for the calculation of the transonic flow field of multistage turbines taking high coolant flow into account. To reduce the processing time, a throughflow method based on the principels of Wu is used for the hub-to-tip calculation. The flow field is obtained by an iterative solution between a three dimensional inviscid hyperbolic time-dependent algorithm with an implicit finite volume method for the blade-to-blade calculations using C-meshes and a single representative meridional S2m-stream surface. Along the S2m-plane with respect to non-orthogonal curvilinear coordinates, the stream function equation governing fluid flow is established. The cooling air inflow inside the blade passage forbids the assumption of a constant mass flow along the main stream direction. To consider the change of the aerodynamic and thermodynamic behaviour, a cooling air model was developed and implemented in the algorithm, which allows the mixing of radially arbitrarily distributed cooling air in the trailing edge section of each blade row. The viscous effects and the influence of cooling air mixing are considered by the use of selected loss correlations for profile-, tip leakage, secondary flow and mixing losses in the S2m-plane in terms of entropy. The method is applied to the four stage high temperature gas turbine Siemens KWU V84.3. The obtained numerical results are in good agreement with the experimental data.

Calculation of Fluid Flow Field and Thermal Field for Air-to-Air Cooled Medium Motor

2014 ◽  
Vol 543-547 ◽  
pp. 362-365
Author(s):  
Tian Hu ◽  
Yan Li ◽  
Ren Yuan Tang
Keyword(s):  
Flow Field ◽  
Thermal Field ◽  
Cooling System ◽  
Three Dimensional ◽  
Cooling Effect ◽  
Computational Fluid Mechanics ◽  
Computational Domain ◽  
Motor Cooling ◽  
Volume Method ◽  
Cooling Air

For an air-to-air cooled medium motor, to ensure the cooling effect of the motor, the physical model of the motor cooling air inside the cooler was built. By the finite volume method according to the computational fluid mechanics (CFD) principle, the three-dimensional turbulent flow field in computational domain was simulated numerically using boundary conditions of the inlet and outlet obtained from engineering calculations. From the result, the thermal field of cooler was calculation. Finally, through the comparison, the cooler cooling the motor cooling effect sufficient play , the outer duct can effectively reduce the internal temperature of the cooling gas duct , the air duct outside the cooling gas declined about 35 °C after cooling the temperature of the air duct, the calculation method is feasible for the motor cooling system design overall foundation .

scholarly journals Improvement of Pump Performance at Off-Design Conditions

1985 ◽  
Author(s):  
J. Paulon ◽  
C. Fradin ◽  
J. Poulain
Keyword(s):  
Experimental Study ◽  
Flow Field ◽  
Mass Flow ◽  
Flow Characteristic ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Pump Performance ◽  
Wide Range ◽  
Mass Flows ◽  
Design Value

Industrial pumps are generally used in a wide range of operating conditions from almost zero mass flow to mass flows larger than the design value. It has been often noted that the head-mass flow characteristic, at constant speed, presents a negative bump as the mass flow is somewhat smaller than the design mass flows. Flow and mechanical instabilities appear, which are unsafe for the facility. An experimental study has been undertaken in order to analyze and if possible to palliate these difficulties. A detailed flow analyzis has shown strong three dimensional effects and flow separations. From this better knowledge of the flow field, a particular device was designed and a strong attenuation of the negative bump was obtained.

Improved Approach to the Streamline Curvature Method in Turbomachinery

1987 ◽  
Vol 109 (3) ◽  
pp. 213-217 ◽  
Author(s):  
S. Abdallah ◽  
R. E. Henderson
Keyword(s):  
Flow Field ◽  
Velocity Gradient ◽  
Numerical Solutions ◽  
Three Dimensional ◽  
Second Order ◽  
Curvilinear Coordinates ◽  
First Order ◽  
Streamline Curvature ◽  
Stators And Rotors ◽  
Streamline Curvature Method

Quasi three dimensional blade-to-blade solutions for stators and rotors of turbomachines are obtained using the Streamline Curvature Method (SLCM). The first-order velocity gradient equation of the SLCM, traditionally solved for the velocity field, is reformulated as a second-order elliptic differential equation and employed in tracing the streamtubes throughout the flow field. The equation of continuity is then used to calculate the velocity. The present method has the following advantages. First, it preserves the ellipticity of the flow field in the solution of the second-order velocity gradient equation. Second, it eliminates the need for curve fitting and strong smoothing under-relaxation in the classical SLCM. Third, the prediction of the stagnation streamlines is a straightforward matter which does not complicate the present procedure. Finally, body-fitted curvilinear coordinates (streamlines and orthogonals or quasi-orthogonals) are naturally generated in the method. Numerical solutions are obtained for inviscid incompressible flow in rotating and non-rotating passages and the results are compared with experimental data.

Three Dimensional Numerical Simulation of Flow Field Inside a Reversible Pumping Station With Symmetric Aerofoil Blade

2008 ◽  
Author(s):  
Li Cheng ◽  
Chao Liu ◽  
Jiren Zhou ◽  
Fangping Tang ◽  
Yan Jin
Keyword(s):  
Flow Field ◽  
Control Volume ◽  
Three Dimensional ◽  
Flow Coefficient ◽  
Viscous Effects ◽  
Total Uncertainty ◽  
Pumping Station ◽  
Pumping System ◽  
Test Loop ◽  
Useful Power

The pumping station with symmetric aerofoil can achieve reversible pumping function. It can keep high reversible efficiency and its flow coefficient is approaching to normal one. At same time, it has the simple structure and is easy to operate and maintain. The flow inside reversible pumping station is very complex and dominated by three dimensional viscous effects. With the rapid progress of computational fluid dynamics, CFD has become an important tool to help to make full understanding of flow. In order to recognize the characteristic of pumping station, the control volume method is used to simulation the flow filed. The RNG k-ε turbulent model and SIMPLEC algorithm are applied to do analysis. Flow field inside symmetric aerofoil blade and passage of pumping station are analyzed in detail. Some computational data, such as computational contour of sections, streamline of pumping system, flow vectors of blade and pressure contour of blade for two different rotate directional, are given in the paper. On the based of the simulation results, efficiency prediction of the pumping station is applied. By calculating the useful power and the hydraulic efficiency at the 11 different discharge points, capabilities of pumping station are predicted. A set of model pumping station with a 300mm blade are made for test. Using the laboratory test loop of which the total uncertainty of measured efficiency is ±0.39%, the hydraulic performance is evaluated and demonstrated. The numerical performances agree well with experiment data.

Effects of Flow Injection From Outer Casing Upon Turbine Nozzle Vane Flow Field

2002 ◽  
Author(s):  
K. Funazaki ◽  
C. F. F. Favaretto ◽  
T. Tanuma
Keyword(s):  
Flow Field ◽  
Flow Injection ◽  
Three Dimensional ◽  
Leading Edge ◽  
Main Stream ◽  
Flow Angle ◽  
Aerodynamic Loss ◽  
Nozzle Vane ◽  
Design Variables ◽  
The Impact

In the present paper steady three-dimensional numerical calculations were performed in order to investigate the effects of flow injection from the outer casing upon turbine nozzle vane flow field. Several test cases were analyzed by applying different nozzle vane configurations such as the blade lean, injection slot width and distance from the leading edge. Numerical simulations were conducted considering the no injection case, 5% and 10% main stream flow injection from the outer casing. The impact of the flow injection design variables and the blade lean angle on the aerodynamic loss in terms of the energy loss coefficient and the outlet flow angle were analyzed through a parametric study.

Numerical Simulation on Cylinder Flow Field of Diesel

2013 ◽  
Vol 712-715 ◽  
pp. 1330-1334
Author(s):  
Yin Dong Song ◽  
Yin Nan Yuan ◽  
Chun Ping Wu ◽  
Yong Wang Li ◽  
Peng Zhe Qi ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Three Dimensional ◽  
Swirl Flow ◽  
Mixing Rate ◽  
Air Mixing ◽  
Reduce Emissions ◽  
Diesel Cylinder ◽  
Cylinder Flow ◽  
Transient Numerical Simulation

Three dimensional transient numerical simulation on cylinder flow field of 4B26 diesel was done by AVL FIRE. Detailed flow field structure of diesel cylinder was calculated. The typical swirl flow and squish flow were established in 4B26 diesel engine chamber. swirl flow and squish flow can increase the fuel and air mixing rate, and can improve diesel combustion and can reduce emissions of pollutants. Oil beam could accelerate the air around it.

Mainstream Aerodynamic Effects due to Wheelspace Coolant Injection in a High-Pressure Turbine Stage: Part II — Aerodynamic Measurements in the Rotational Frame

2001 ◽  
Author(s):  
Christopher McLean ◽  
Cengiz Camci ◽  
Boris Glezer
Keyword(s):  
High Pressure ◽  
Guide Vane ◽  
Pressure Coefficient ◽  
Three Dimensional ◽  
Axial Flow ◽  
Main Stream ◽  
Turbine Stage ◽  
High Pressure Turbine ◽  
Coolant Injection ◽  
Cooling Air

The current paper deals with the aerodynamic measurements in the rotational frame of reference of the Axial Flow Turbine Research Facility (AFTRF) at the Pennsylvania State University. Stationary frame measurements of “Mainstream Aerodynamic Effects Due to Wheelspace Coolant Injection in a High Pressure Turbine Stage” were presented in part-I of this paper. The relative aerodynamic effects associated with rotor – nozzle guide vane (NGV) gap coolant injections were investigated in the rotating frame. Three-dimensional velocity vectors including exit flow angles were measured at the rotor exit. This study quantifies the secondary effects of the coolant injection on the aerodynamic and performance character of the stage main stream flow for root injection, radial cooling and impingement cooling. Current measurements show that even a small quantity (1%) of cooling air can have significant effects on the performance and exit conditions of the high pressure turbine stage. Parameters such as the total pressure coefficient, wake width, and three-dimensional velocity field show significant local changes. It is clear that the cooling air disturbs the inlet end-wall boundary layer to the rotor and modifies secondary flow development thereby resulting in large changes in turbine exit conditions. Effects are the strongest from the hub to midspan. Negligible effect of the cooling flow can be seen in the tip region.

Numerical Investigation of Effect of Recess Vane Casing Treatments on an Axial Lift Fan Performance

2017 ◽  
Author(s):  
Xiangyi Chen ◽  
Wuli Chu ◽  
Haoguang Zhang ◽  
Jinge Li ◽  
Jinhua Lang
Keyword(s):  
Flow Field ◽  
Mass Flow ◽  
Pressure Pulse ◽  
Three Dimensional ◽  
Flow Distribution ◽  
Leading Edge ◽  
Sea Waves ◽  
Stall Margin ◽  
Blade Tip ◽  
Casing Treatments

Lift fans fitted on hovercraft are often subjected to pressure pulse generated by the sea waves. With a high pressure from the pressure pulse, the fan is driven transiently to a low mass flow rate operating point. The probability that a stall can happen is relatively high. The recess vane casing treatment (RVCT) is used to improve the axial lift fan’s stall margin in this paper. Using the NUMECA software, the fan with solid casing and different RVTC geometry and its flow field are analyzed. The geometry modifications include blade chord exposure variation and cavity outlet axial span. Compared with the solid case, all casing treatments result in a reduction in efficiency. The blade chord exposure is a key factor that affects the efficiency. The RVCT with minimum blade chord exposure provides an inferior stall margin of −0.293% while the others provide 6% to 15% stall margin improvement, respectively. In the study of the physical flow mechanisms, visualization can provide an insight into the flow field. This reveals that characteristics of the mainstream flow are different between near stall point and design point for the solid casing fan. The three-dimensional (3D) flow field suggests that the flow capacity near the blade tip is damaged by the blockage. The rotor blade is considered as a critical tip based on its stalling behavior. By applying RVCT, the flow field near blade tip is modified, and local mass flow ahead of blade leading edge increases while flow distribution of blade downstream along spanwise is almost the same with the solid casing fan. Also, the flow exchange between RVCT and mainstream is established through the introduction of RVCT. In quantitative analysis, the flow exchange is quantified based on the mass flow passing through the cavity. The ability of RVCT to stabilize the fan is based on the size of cavity, the more mass flow passes through cavity, the more stall margin enhancement can be obtained by the fan. However, the flow exchange between RVCT and mainstream can cause intense mixing, which can lead to efficiency loss.

Computation of the Flow Field of Transonic Axial Compressor by Steady Arbitrary Lagrangian Eulerian Formulation

2008 ◽  
Author(s):  
Adel Ghenaiet ◽  
Nouredine Djeghri
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Arbitrary Lagrangian Eulerian ◽  
Viscous Effects ◽  
Stability Range ◽  
Transonic Compressor ◽  
Ale Formulation ◽  
Transonic Axial Compressor ◽  
Residual Smoothing

This paper presents a multi-block solver dealing with an inviscid three dimensional compressible flow through a transonic compressor blading. For efficient computations of the 3D time dependant Euler equations, this solver that we have developed has been cast within a stationary ALE ‘Arbitrary Lagrangian Eulerian’. The main contribution of this paper is by consolidating this ALE formulation, to alleviate the shortcomings linked to rotation effects and the mixed relative subsonic–supersonic inlet flow conditions, which are now simply implemented through an absolute subsonic flow velocity. The finite volume based solver is using the central differencing scheme known as JST (Jameson-Schmidt-Turkel). The explicit multistage Runge-Kutta algorithm is used as a pseudo time marching to the steady-state, coupled with two convergence accelerating techniques; the variable local time-stepping and the implicit residual smoothing procedure. The adaptive implicit residual smoothing has extended the stability range of this explicit scheme, and proved to be successful in accelerating the rate of convergence. This code is currently being extended to include viscous effects, where fluxes are discretized based on Green’s theorem. To support this solver, an H type grid generator based on algebraic and elliptic methods has been developed. The segmentation of the complete domain into smaller blocks has provided full topological and geometrical flexibilities. The code was used to compute the flow field of a transonic axial compressor NASA rotor 37, and comparisons between the calculations and some available experimental data under the design speed and part speed, show qualitatively good agreement.

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