Turbomachinery Loss Analysis: The Relationship Between Mechanical Work Potential and Entropy Analyses

2021 ◽  
Author(s):  
John Leggett ◽  
Yaomin Zhao ◽  
Edward S. Richardson ◽  
Richard D. Sandberg
Keyword(s):  
High Pressure ◽  
Viscous Dissipation ◽  
Three Dimensional ◽  
Mechanical Work ◽  
Potential Analysis ◽  
Entropy Loss ◽  
Loss Analysis ◽  
Analysis Methods ◽  
High Pressure Compressor ◽  
Reference Pressure

Abstract Physics-based loss analysis methods have been developed to interpret the detailed three-dimensional and time-dependent predictions of turbomachinery CFD simulations. This paper contrasts two analysis methods for assessing loss: entropy loss analysis (Zhao & Sandberg, GT2019-90126) and mechanical work potential analysis (Miller, GT2013-95488). The two individual analyses are applied to high-fidelity simulation data for linear high-pressure compressor and high-pressure turbine cascades. The results show each analysis captures the loss generating processes in different ways, corresponding to different terms in their equations. The key loss generation processes are shown to be turbulent and mean viscous dissipation in the mechanical work potential analysis, and mean viscous dissipation and turbulence production in the entropy loss analysis. A relationship between the two approaches is derived rigorously, providing a means to convert between the results of the two approaches, enabling designers to assess individual stage performance using the entropy-based analysis and multiple stages in terms of mechanical work potential, by using the same reference pressure.

Measurement and Computation of Heat Transfer in High-Pressure Compressor Drum Geometries With Axial Throughflow

1997 ◽  
Vol 119 (1) ◽  
pp. 51-60 ◽  
Author(s):  
C. A. Long ◽  
A. P. Morse ◽  
P. G. Tucker
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Multigrid Algorithm ◽  
Numerical Predictions ◽  
High Pressure Compressor ◽  
Dependent Form ◽  
Pressure Compressor

This paper makes comparisons between CFD computations and experimental measurements of heat transfer for the axial throughflow of cooling air in a high-pressure compressor spool rig and a plane cavity rig. The heat transfer measurements are produced using fluxmeters and by the conduction solution method from surface temperature measurements. Numerical predictions are made by solving the Navier–Stokes equations in a full three-dimensional, time-dependent form using the finite-volume method. Convergence is accelerated using a multigrid algorithm and turbulence modeled using a simple mixing length formulation. Notwithstanding systematic differences between the measurements and the computations, the level of agreement can be regarded as promising in view of the acknowledged uncertainties in the experimental data, the limitations of the turbulence model and, perhaps more importantly, the modest grid densities used for the computations.

scholarly journals Research of the possibility of improving the traction and economic characteristics of a supersonic passenger aircraft engine through minimal modifications to the high-pressure compressor

2021 ◽  
Vol 2094 (4) ◽  
pp. 042055
Author(s):  
D Yu Strelets ◽  
S A Serebryansky ◽  
M V Shkurin
Keyword(s):  
High Pressure ◽  
Numerical Model ◽  
Thermodynamic Model ◽  
Gas Dynamics ◽  
High Speed ◽  
Three Dimensional ◽  
Aircraft Engine ◽  
High Pressure Compressor ◽  
Passenger Aircraft ◽  
Pressure Compressor

Abstract In this paper, the possibilities of improving the traction and economic characteristics of a by-pass turbojet engine of a high-speed passenger aircraft due to minimal modifications of the high-pressure compressor. A thermodynamic model of the investigated engine of a new design in a three-dimensional layout was formed using an automated multicriteria optimization process. A computational assessment of the change in the characteristics of compressor modifications is carried out based on a numerical model of gas dynamics.

1995 ASME Gas Turbine Award Paper: Development and Application of a Multistage Navier–Stokes Flow Solver: Part II—Application to a High-Pressure Compressor Design

1998 ◽  
Vol 120 (2) ◽  
pp. 215-223 ◽  
Author(s):  
C. R. LeJambre ◽  
R. M. Zacharias ◽  
B. P. Biederman ◽  
A. J. Gleixner ◽  
C. J. Yetka
Keyword(s):  
High Pressure ◽  
Three Dimensional ◽  
Tip Clearance ◽  
Navier Stokes ◽  
Flow Solver ◽  
Stall Margin ◽  
High Pressure Compressor ◽  
Compressor Design ◽  
Flow Through ◽  
Pressure Compressor

Two versions of a three-dimensional multistage Navier–Stokes code were used to optimize the design of an eleven-stage high-pressure compressor. The first version of the code utilized a “mixing plane” approach to compute the flow through multistage machines. The effects due to tip clearances and flowpath cavities were not modeled. This code was used to minimize the regions of separation on airfoil and endwall surfaces for the compressor. The resulting compressor contained bowed stators and rotor airfoils with contoured endwalls. Experimental data acquired for the HPC showed that it achieved 2 percent higher efficiency than a baseline machine, but it had 14 percent lower stall margin. Increased stall margin of the HPC was achieved by modifying the stator airfoils without compromising the gain in efficiency as demonstrated in subsequent rig and engine tests. The modifications to the stators were defined by using the second version of the multistage Navier–Stokes code, which models the effects of tip clearance and endwall flowpath cavities, as well as the effects of adjacent airfoil rows through the use of “bodyforces” and “deterministic stresses.” The application of the Navier–Stokes code was assessed to yield up to 50 percent reduction in the compressor development time and cost.

scholarly journals Surface roughness of real operationally used compressor blade and blisk

2019 ◽  
Vol 233 (14) ◽  
pp. 5321-5330 ◽  
Author(s):  
Philipp Gilge ◽  
Andreas Kellersmann ◽  
Jens Friedrichs ◽  
Jörg R Seume
Keyword(s):  
Surface Roughness ◽  
High Pressure ◽  
Laser Scanning ◽  
Flow Direction ◽  
Three Dimensional ◽  
Pressure Rise ◽  
Aircraft Engine ◽  
Rotor Blades ◽  
High Pressure Compressor ◽  
Pressure Compressor

Deterioration of axial compressors is in general a major concern in aircraft engine maintenance. Among other effects, roughness in high-pressure compressor reduces the pressure rise and thus efficiency, thereby increasing the specific fuel consumption of an engine. Therefore, it is important to improve the understanding of roughness on compressor blading and their impact on compressor performance. To investigate the surface roughness of rotor blades of a compressors, different stages of an axial high-pressure compressor and a first-stage blisk (BLade–Integrated–dISK) of a regional aircraft engine is measured by a three-dimensional laser scanning microscope. Fundamental types of roughness structures can be identified: impacts in different sizes, depositions as isotropically distributed single elements with steep flanks and anisotropic roughness structures direct approximately normal to the flow direction. To characterise and quantify the roughness structures in more detail, roughness parameters were determined from the measured surfaces. The quantification showed that the roughness height varies through the compressor depending on the stage, position and the blade side. Overall complex roughness structures of different shape, height and size are detected regardless of the type of the blades.

scholarly journals Development and Application of a Multistage Navier-Stokes Flow Solver: Part II — Application to a High Pressure Compressor Design

1995 ◽  
Author(s):  
C. R. LeJambre ◽  
R. M. Zacharias ◽  
B. P. Biederman ◽  
A. J. Gleixner ◽  
C. J. Yetka
Keyword(s):  
High Pressure ◽  
Three Dimensional ◽  
Tip Clearance ◽  
Navier Stokes ◽  
Flow Solver ◽  
Stall Margin ◽  
High Pressure Compressor ◽  
Compressor Design ◽  
Flow Through ◽  
Pressure Compressor

Two versions of a three dimensional multistage Navier-Stokes code were used to optimize the design of an eleven stage high pressure compressor. The first version of the code utilized a “mixing plane” approach to compute the flow through multistage machines. The effects due to tip clearances and flowpath cavities were not modeled. This code was used to minimize the regions of separation on airfoil and endwall surfaces for the compressor. The resulting compressor contained bowed stators and rotor airfoils with contoured endwalls. Experimental data acquired for the HPC showed that it achieved 2% higher efficiency than a baseline machine, but it had 14% lower stall margin. Increased stall margin of the HPC was achieved by modifying the stator airfoils without compromising the gain in efficiency as demonstrated in subsequent rig and engine tests. The modifications to the stators were defined by using the second version of the multistage Navier-Stokes code, which models the effects of tip clearance and endwall flowpath cavities, as well as the effects of adjacent airfoil rows through the use of “bodyforces” and “deterministic stresses”. The application of the Navier-Stokes code was assessed to yield up to 50% reduction in the compressor development time and cost.

Probabilistic CFD Simulation of a High-Pressure Compressor Stage Taking Manufacturing Variability Into Account

2010 ◽  
Author(s):  
Alexander Lange ◽  
Matthias Voigt ◽  
Konrad Vogeler ◽  
Henner Schrapp ◽  
Erik Johann ◽  
...  
Keyword(s):  
High Pressure ◽  
Point Cloud ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Parameter Vector ◽  
Compressor Blades ◽  
The Monte Carlo Method ◽  
High Pressure Compressor ◽  
Pressure Compressor

The present paper addresses a non-deterministic CFD simulation of a high-pressure compressor (HPC) stage. The investigation focuses on the determination of the influence of the manufacturing scatter of compressor blades on the aerodynamic performance of the analyzed HPC stage. A set of 150 blades was scanned using an optical 3D digitizer to obtain a three-dimensional point cloud representing the surface of the blades. Classical profile parameters were identified at several sections of constant spanwise coordinate. The radial stacking of these parameters forms a parameter vector that constructs the airfoil model of each scanned blade. Consequently these parameters were used to define the geometric variability of the entire measured blade set. A statistical analysis of the distribution of these parameters defines the input data of the probabilistic 3D CFD simulation. The Monte-Carlo method is used to identify the scatter of the performance values of the HPC stage and their sensitivity to the geometric variability of profile parameters.

Measurement and Computation of Heat Transfer in High Pressure Compressor Drum Geometries With Axial Throughflow

1995 ◽  
Author(s):  
Christopher A. Long ◽  
Alan P. Morse ◽  
Paul G. Tucker
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Multigrid Algorithm ◽  
Numerical Predictions ◽  
High Pressure Compressor ◽  
Dependent Form ◽  
Pressure Compressor

This paper makes comparisons between CFD computations and experimental measurements of heat transfer for the axial throughflow of cooling air in a high-pressure compressor spool rig and a plane cavity rig. The heat transfer measurements are produced using fluxmeters and by the conduction solution method from surface temperature measurements. Numerical predictions are made by solving the Navier-Stokes equations in a full three-dimensional, time-dependent form using the finite-volume method. Convergence is accelerated using a multigrid algorithm and turbulence modelled using a simple mixing length formulation. Notwithstanding systematic differences between the measurements and the computations, the level of agreement can be regarded as promising in view of the acknowledged uncertainties in the experimental data, the limitations of the turbulence model and, perhaps more importantly, the modest grid densities used for the computations.

Review on the aerodynamics of intermediate compressor duct

2020 ◽  
Vol 14 (4) ◽  
pp. 7446-7468
Author(s):  
Manish Sharma ◽  
Beena D. Baloni
Keyword(s):  
High Pressure ◽  
Pressure Loss ◽  
Flow Analysis ◽  
Outer Wall ◽  
Optimization Techniques ◽  
Optimum Pressure ◽  
Research Areas ◽  
Static Pressure Distribution ◽  
High Pressure Compressor ◽  
Pressure Compressor

In a turbofan engine, the air is brought from the low to the high-pressure compressor through an intermediate compressor duct. Weight and design space limitations impel to its design as an S-shaped. Despite it, the intermediate duct has to guide the flow carefully to the high-pressure compressor without disturbances and flow separations hence, flow analysis within the duct has been attractive to the researchers ever since its inception. Consequently, a number of researchers and experimentalists from the aerospace industry could not keep themselves away from this research. Further demand for increasing by-pass ratio will change the shape and weight of the duct that uplift encourages them to continue research in this field. Innumerable studies related to S-shaped duct have proven that its performance depends on many factors like curvature, upstream compressor’s vortices, swirl, insertion of struts, geometrical aspects, Mach number and many more. The application of flow control devices, wall shape optimization techniques, and integrated concepts lead a better system performance and shorten the duct length.  This review paper is an endeavor to encapsulate all the above aspects and finally, it can be concluded that the intermediate duct is a key component to keep the overall weight and specific fuel consumption low. The shape and curvature of the duct significantly affect the pressure distortion. The wall static pressure distribution along the inner wall significantly higher than that of the outer wall. Duct pressure loss enhances with the aggressive design of duct, incursion of struts, thick inlet boundary layer and higher swirl at the inlet. Thus, one should focus on research areas for better aerodynamic effects of the above parameters which give duct design with optimum pressure loss and non-uniformity within the duct.

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