scholarly journals Through Flow Calculation in Axial Flow Turbines Using a Quasi-Orthogonal Solver

1998 ◽  
Author(s):  
F. Noera ◽  
A. Satta
Keyword(s):  
Numerical Investigation ◽  
Mesh Generation ◽  
Axial Flow ◽  
Operating Conditions ◽  
Flow Solver ◽  
Turbine Performance ◽  
Through Flow ◽  
New Formulation ◽  
High Level ◽  
Semi Empirical

Application of CFD investigating and analysing axial flow turbomachines has reached, in the last years, a high level of accuracy and thus can be applied quite routinely in the prediction of different kinds of flow. The numerical investigation of axial flow turbine performance is of great interest because of the importance of correct product design and of the behaviour in off-design conditions. In this paper a new formulation of the radial equilibrium equation is presented. This formulation is particularly suitable for turbomachinery numerical investigation, and is applied in a quasi-orthogonal through flow solver. All the terms involved in the proposed formulation have been taken into account in order to solve the more general problem. Mesh generation and blade geometrical representation are simplified in order to reduce the pre-processing work. In order to evaluate cascade losses and deviation angle, Ainley- and Mathieson semi-empirical correlations and their correction proposed by Dunham and Came and Kacker and Okapuu have been utilised. The four stages Hannover experimental turbine and the Cambridge one have been analysed in different operating conditions; numerical results have been compared with the experimental ones to evaluate the level of accuracy of the proposed procedure.

scholarly journals Aerodynamic Analysis of Multistage Turbomachinery Flows in Support of Aerodynamic Design

1999 ◽  
Author(s):  
John J. Adamczyk
Keyword(s):  
Unsteady Flow ◽  
Axial Flow ◽  
Operating Conditions ◽  
Design Environment ◽  
Cfd Simulations ◽  
Average Flow ◽  
Flow Models ◽  
Time Average ◽  
Semi Empirical ◽  
Future Work

This paper summarizes the state of 3D CFD based models of the time average flow field within axial flow multistage turbomachines. Emphasis is placed on models which are compatible with the industrial design environment and those models which offer the potential of providing credible results at both design and off-design operating conditions. The need to develop models which are free of aerodynamic input from semi-empirical design systems is stressed. The accuracy of such models is shown to be dependent upon their ability to account for the unsteady flow environment in multistage turbomachinery. The relevant flow physics associated with some of the unsteady flow processes present in axial flow multistage machinery are presented along with procedures which can be used to account for them in 3D CFD simulations. Sample results are presented for both axial flow compressors and axial flow turbines which help to illustrate the enhanced predictive capabilities afforded by including these procedures in 3D CFD simulations. Finally, suggestions are given for future work on the development of time average flow models.

Experimental and Numerical Investigation of Stator Exit Flow Field of an Automotive Torque Converter

1996 ◽  
Vol 118 (4) ◽  
pp. 835-843 ◽  
Author(s):  
B. V. Marathe ◽  
B. Lakshminarayana ◽  
Y. Dong
Keyword(s):  
Flow Field ◽  
Secondary Flow ◽  
Numerical Investigation ◽  
Three Dimensional ◽  
Axial Flow ◽  
Torque Converter ◽  
Operating Conditions ◽  
Navier Stokes ◽  
Complex Flow ◽  
Rate Of Decay

The objective of this investigation is to understand the nature of the complex flow field inside each element of the torque converter through a systematic experimental and numerical investigation of the flow field. A miniature five-hole probe was used to acquire the data at the exit of the stator at several operating conditions. The flow field is found to be highly three dimensional with substantial flow deviations, and secondary flow at the exit of the stator. The secondary flow structure, caused by the upstream radial variation of the through flow, induces flow overturning near the core. Flow separation near the shell causes flow underturning in this region. The rate of decay of stator wake is found to be slower than that observed in the wakes of axial flow turbine nozzles. The flow predictions by a Navier–Stokes code are in good agreement with the pressure and the flow field measured at the exit of the stator at the design and the off-design conditions.

An Integrated Design System for Fans, Compressors, and Turbines: Part 2 — Interactive Interface

2004 ◽  
Author(s):  
Wolfgang A. Sandel ◽  
Max J. Miller
Keyword(s):  
Integrated Design ◽  
Flow Path ◽  
Design System ◽  
Aerodynamic Design ◽  
Flow Solver ◽  
Design Considerations ◽  
The Past ◽  
Interactive Interface ◽  
Through Flow ◽  
High Level

A new, comprehensive, flexible, integrated design system for the aerodynamic design of fans, compressors, and turbines was developed during the past decade. It operates in both batch and interactive modes. The system contains a flow path generator, a through-flow solver, a stacked airfoil geometry generator, and a flank-milled airfoil geometry generator. This paper describes the interactive interface in more detail. In particular, it describes the design considerations, appearance, and functionality of the interactive interface. Top level requirements were established before the interface was designed. These requirements are explained and some of the key reasoning that drove the high level design of the interface is discussed. The four principal windows in the interface are described in detail. The interactive interface that was developed has significantly increased the productivity of fan, compressor and turbine aero designers.

Experimental and Numerical Investigation of Stator Exit Flow Field of an Automotive Torque Converter

1994 ◽  
Author(s):  
B. V. Marathe ◽  
B. Lakshminarayana ◽  
Y. Dong
Keyword(s):  
Flow Field ◽  
Secondary Flow ◽  
Numerical Investigation ◽  
Three Dimensional ◽  
Axial Flow ◽  
Torque Converter ◽  
Operating Conditions ◽  
Navier Stokes ◽  
Complex Flow ◽  
Rate Of Decay

The objective of this investigation is to understand the nature of the complex flow field inside each element of the torque converter through a systematic experimental and numerical investigation of the flow field. A miniature five-hole probe was used to acquire the data at the exit of the stat or at several operating conditions. The flow field is found to be highly three-dimensional with substantial flow deviations, and secondary flow at the exit of the stator. The secondary flow structure, caused by the upstream radial variation of the through flow, induces flow overturning near the core. Flow separation near the shell causes flow underturning in this region. The rate of decay of stator wake is found to be slower than that observed in the wakes of axial flow turbine nozzles. The flow predictions by a Navier-Stokes code are in good agreement with the pressure and the flow field measured at the exit of the stator at the design and the off-design conditions.

scholarly journals Effect of the Beam Element Geometric Formulation on the Wind Turbine Performance and Structural Dynamics

2017 ◽  
Author(s):  
Virgile Delhaye ◽  
Madjid Karimirad ◽  
Petter Andreas Berthelsen
Keyword(s):  
Wind Turbine ◽  
Operating Conditions ◽  
Beam Model ◽  
Dynamic Simulations ◽  
Turbine Performance ◽  
Operating Load ◽  
New Formulation ◽  
Static Conditions ◽  
Geometric Formulation

In this paper, the original double symmetric cross section beam formulation in RIFLEX used to model the blades is compared against a newly implemented generalised beam formulation, allowing for eccentric mass, shear and elastic centres. The generalised beam formulation is first evaluated against an equivalent ABAQUS beam model (Using the generalised beam formulation implemented in ABAQUS) which consists of DTU 10MW RWT (reference wind turbine) blade in static conditions. A static displacement is applied to the tip, which is close to an operating load. The results appear very similar and ensure that the implementation is correct. The extended beam formulation is afterwards used on the Land-based 10MW turbine from DTU with external controller. This case study aims at evaluating the effect of the newly implemented formulation on realistic, flexible structure. During the study, the blades were discretised using both the old and new formulation, and dynamic simulations were performed. The effect of the beam formulation was evaluated using several wind conditions that are thought to be characteristic of operating conditions. Results show slight difference between two formulations but could be more significant for next generation flexible blades.

Numerical Investigation of the Solidity Effect on Linear Compressor Cascades

2014 ◽  
Author(s):  
J. Sans ◽  
M. Resmini ◽  
J.-F. Brouckaert ◽  
S. Hiernaux
Keyword(s):  
Numerical Investigation ◽  
State Of The Art ◽  
Leading Edge ◽  
Operating Conditions ◽  
Compressor Cascade ◽  
Minimum Loss ◽  
Low Speed ◽  
High Mach ◽  
The Stability ◽  
The Impact

Solidity in compressors is defined as the ratio of the aerodynamic chord over the peripheral distance between two adjacent blades, the pitch. This parameter is simply the inverse of the pitch-to-chord ratio generally used in turbines. Solidity must be selected at the earliest design phase, i.e. at the level of the meridional design and represents a crucial step in the whole design process. Most of the existing studies on this topic rely on low-speed compressor cascade correlations from Carter or Lieblein. The aim of this work is to update those correlations for state-of-the-art controlled diffusion blades, and extend their application to high Mach number flow regimes more typical of modern compressors. Another objective is also to improve the physical understanding of the solidity effect on compressor performance and stability. A numerical investigation has been performed using the commercial software FINE/Turbo. Two different blade profiles were selected and investigated in the compressible flow regime as an extension to the low-speed data on which the correlations are based. The first cascade uses a standard double circular arc profile, extensively referenced in the literature, while the second configuration uses a state-of-the-art CDB, representative of low pressure compressor stator mid-span profile. Both profiles have been designed with the same inlet and outlet metal angles and the same maximum thickness but the camber and thickness distributions, the stagger angle and the leading edge geometry of the CDB have been optimized. The determination of minimum loss, optimum incidence and deviation is addressed and compared with existing correlations for both configurations and various Mach numbers that have been selected in order to match typical booster stall and choke operating conditions. The emphasis is set on the minimum loss performance at mid-span. The impact of the solidity on the operating range and the stability of the cascade are also studied.

Powder Spheroidization Using Induction Plasma Technology

2000 ◽  
Author(s):  
N.M. Dignard ◽  
M.I. Boulos
Keyword(s):  
Energy Efficiency ◽  
Maximum Energy ◽  
Operating Conditions ◽  
Side Reactions ◽  
Induction Plasma ◽  
Silica Alumina ◽  
Change In The Mean ◽  
The Individual ◽  
Semi Empirical ◽  
Objective Being

Abstract An experimental study of the spheroidization efficiency of induction plasma processes was completed. The main objective being to obtain models which could be subsequently used for the prediction of the spheroidization efficiency for various powders and plasma operating conditions. Silica, alumina, chromium oxide and zirconia powders were treated during the experimentation. For the plasma treatment of the powders the installation used had a maximum available power of 50 kW with an operating frequency of 3 MHz. Operating conditions were varied such to minimize side reactions and the evaporation of powders. The resulting powders did show the presence of cavities and a slight change in the mean diameters. The maximum energy efficiency based semi-empirical model did predict the spheroidization efficiency of the particles beyond a defined critical point known as the maximum energy efficiency point. For the model, the maximum energy efficiency is distinct for the individual powders but remain within a defined range which is reflected in the small variations in the Z constant.

Proving the Labeled Interval Calculus for Inferences on Catalogs

1990 ◽  
Author(s):  
Walid Habib ◽  
Allen C. Ward
Keyword(s):  
Mechanical Design ◽  
Formal System ◽  
Constraint Propagation ◽  
Operating Conditions ◽  
Manufacturing Processes ◽  
Entire System ◽  
High Level Language ◽  
Design Problems ◽  
High Level ◽  
Interval Constraint

Abstract The “labeled interval calculus” is a formal system that performs quantitative inferences about sets of artifacts under sets of operating conditions. It refines and extends the idea of interval constraint propagation, and has been used as the basis of a program called a “mechanical design compiler,” which provides the user with a “high level language” in which design problems for systems to be built of cataloged components can be quickly and easily formulated. The compiler then selects optimal combinations of catalog numbers. Previous work has tested the calculus empirically, but only parts of the calculus have been proven mathematically. This paper presents a new version of the calculus and shows how to extend the earlier proofs to prove the entire system. It formalizes the effects of toleranced manufacturing processes through the concept of a “selectable subset” of the artifacts under consideration. It demonstrates the utility of distinguishing between statements which are true for all artifacts under consideration, and statements which are merely true for some artifact in each selectable subset.

Interaction Between Two Closely Spaced Azimuthing Thrusters

1998 ◽  
Vol 42 (01) ◽  
pp. 15-32 ◽  
Author(s):  
Paul Brandner ◽  
Martin Renilson
Keyword(s):  
Mathematical Model ◽  
Satisfactory Agreement ◽  
Vehicle Dynamics ◽  
Operating Conditions ◽  
Towing Tank ◽  
Empirical Relations ◽  
Series Of Experiments ◽  
Flow Effects ◽  
Semi Empirical

To assist in predicting the performance of omni-directional propelled vehicles a series of experiments has been conducted to measure the interaction between two closely spaced ductedazimuthing thrusters. The thrusters were tested below a shallow draft ground board in a towing tank at a spacing of approximately 2 propeller diameters. Measurements were made of forces acting on a single thruster for a range of operating conditions and similarly on two thrusters for a range of relative positions. The results show that forces from the trailing thruster are heavily affected by interaction, particularly due to impingement of the race from the leading thruster, where as forces from the leading thruster remain essentially unaffected despite its proximity to the trailing thruster. A semi-empirical mathematical model suitable for simulation of omni-directional vehicle dynamics is presented. The model is based on the trajectory of the race from the leading thruster derived from momentum considerations with additional empirical relations to account for other more minor flow effects. Comparison of the predicted and measured results show satisfactory agreement.

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