The Control of Non-Axisymmetric Flow in Axial Turbomachinery Using Circumferentially Varying Stator Exit Angles

2000 ◽  
Author(s):  
Jonathan Taylor ◽  
Tom Hynes
Keyword(s):  
Design Method ◽  
Axisymmetric Flow ◽  
Three Dimensional ◽  
Design Strategies ◽  
Inlet Distortion ◽  
Alternative Approach ◽  
Blade Row ◽  
Actuator Disc ◽  
Flow Through ◽  
The Impact

Turbomachinery operating in distorted flowfields is often very close to the sources of the distortion, and can influence the flowfield distortions at its inlet and outlet. Several techniques are available to reduce the impact of an upstream-running outlet distortion on the turbomachinery by introducing circumferential variation in the most downstream stator row. However, these techniques assume that the upstream-running distortion is not changed by the modifications to the turbomachinery, and none of them addresses the issue of inlet distortion, either on its own or in combination with outlet distortion. A methodology to design circumferentially varying stator angles has been developed. This is based on a two-dimensional linearisation of the distorted flow through the turbomachinery, combined with information from three-dimensional flowfield calculations. The resulting new design method has been applied to an installed lift fan operating with considerable inlet and outlet distortion. The distorted flow through the lift fan is computed by a three-dimensional numerical method incorporating an actuator disc blade row model. The new design method is then used to produce several redesigned builds with circumferentially varying stator exit angles. The three-dimensional flow through the new builds is computed, and compared with flow through the axisymmetric fan. The calculations show that existing non-axisymmetric design strategies may not be applicable to installations having large flowfield distortions. An alternative approach based on unsteady rotor loading is presented, and relatively small stator exit angle variations are shown to produce significant reductions in this quantity.

scholarly journals Semi-Inverse Design of Compressor Cascades, Including Supersonic Inflow

1990 ◽  
Author(s):  
A. Kirschner ◽  
H. Stoff
Keyword(s):  
Flow Field ◽  
Design Method ◽  
Axisymmetric Flow ◽  
Three Dimensional ◽  
Design Procedure ◽  
Meridional Plane ◽  
Simple Method ◽  
Blade Loading ◽  
Through Flow ◽  
Blade Element

A cascade design-method is presented which complements the meridional through-flow design procedure of turbomachines. Starting from an axisymmetric flow field and the streamline geometry in the meridional plane this simple method produces a solution for the quasi three-dimensional flow field and the blade-element geometry on corresponding stream surfaces. In addition, it provides intra-blade data on loss and turning required for a consistent design and a convenient means of optimizing blade loading. The purpose of this paper is to describe the theoretical basis of the method and to illustrate its application in the design of transonic compressors.

scholarly journals Spatial Baseline Optimization for Spaceborne Multistatic SAR Tomography Systems

Sensors ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 2106 ◽  
Author(s):  
Jiuchao Zhao ◽  
Anxi Yu ◽  
Yongsheng Zhang ◽  
Xiaoxiang Zhu ◽  
Zhen Dong
Keyword(s):  
Surface Deformation ◽  
Design Method ◽  
Geometric Model ◽  
Three Dimensional ◽  
Optimization Method ◽  
Deformation Measurement ◽  
Experimental Simulation ◽  
Baseline Design ◽  
Imaging Performance ◽  
The Impact

Spaceborne multistatic synthetic aperture radar (SAR) tomography (SMS-TomoSAR) systems take full advantage of the flexible configuration of multistatic SAR in the space, time, phase, and frequency dimensions, and simultaneously achieve high-precision height resolution and low-deformation measurement of three-dimensional ground scenes. SMS-TomoSAR currently poses a series of key issues to solve, such as baseline optimization, spatial transmission error estimation and compensation, and the choice of imaging algorithm, which directly affects the performance of height-dimensional imaging and surface deformation measurement. This paper explores the impact of baseline distribution on height-dimensional imaging performance for the baseline optimization issue, and proposes a feasible baseline optimization method. Firstly, the multi-base multi-pass baselines of an SMS-TomoSAR system are considered equivalent to a group of multi-pass baselines from monostatic SAR. Secondly, we establish the equivalent baselines as a symmetric-geometric model to characterize the non-uniform characteristic of baseline distribution. Through experimental simulation and model analysis, an approximately uniform baseline distribution is shown to have better SMS-TomoSAR imaging performance in the height direction. Further, a baseline design method under uniform-perturbation sampling with Gaussian distribution error is proposed. Finally, the imaging performance of different levels of perturbation is compared, and the maximum baseline perturbation allowed by the system is given.

Excess Streamwise Vorticity and Its Role in Secondary Flow

1987 ◽  
Vol 201 (6) ◽  
pp. 413-420 ◽  
Author(s):  
P W James
Keyword(s):  
Secondary Flow ◽  
Gas Turbines ◽  
Three Dimensional ◽  
Point Of View ◽  
Streamwise Vorticity ◽  
Three Dimensional Flow ◽  
Approximate Methods ◽  
Blade Row ◽  
Flow Through ◽  
Loss Term

The purpose of this paper is, firstly, to show how the concept of excess secondary vorticity arises naturally from attempts to recover three-dimensional flow details lost in passage-averaging the equations governing the flow through gas turbines. An equation for the growth of excess streamwise vorticity is then derived. This equation, which allows for streamwise entropy gradients through a prescribed loss term, could be integrated numerically through a blade-row to provide the excess vorticity at the exit to a blade-row. The second part of the paper concentrates on the approximate methods of Smith (1) and Came and Marsh (2) for estimating this quantity and demonstrates their relationship to each other and to the concept of excess streamwise vorticity. Finally the relevance of the results to the design of blading for gas turbines, from the point of view of secondary flow, is discussed.

scholarly journals Ultra-High Early Strength Cementitious Grout Suitable for Additive Manufacturing Applications Fabricated by Using Graphene Oxide and Viscosity Modifying Agents

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2900
Author(s):  
Alyaa Mohammed ◽  
Nihad Tareq Khshain Al-Saadi
Keyword(s):  
Graphene Oxide ◽  
Additive Manufacturing ◽  
3D Printing ◽  
Design Method ◽  
Three Dimensional ◽  
Cementitious Materials ◽  
Fresh Properties ◽  
Manufacturing Applications ◽  
Mechanical Strengths ◽  
The Impact

One of the considerable challenges in the design of cementitious mixtures for additive manufacturing/three-dimensional (3D) printing applications is achieving both suitable fresh properties and significant mechanical strengths. This paper presents the use of graphene oxide (GO) as a promising nano reinforcement material with the potential to improve the printing feasibility and quality of a 3D printed cementitious matrix. Additionally, in this study, a viscosity modifying agent (VMA) was employed as a chemical additive to attain the required consistency and flow. The printed mixture was fabricated using various cementitious materials and waste materials. This study investigated the impact of GO and VMA on the enhancement of the 3D printing of cementitious composites through several tests. A flow test was conducted using the flow table test. The results showed a high fluidity and practical consistency, which are essential for nozzle pumping and accurateness in printed shapes. Furthermore, the bleeding test showed minimal bleeding up to hardening, and a considerable self-cleaning ability was noted during handling when conducting examinations of fresh properties. For hardened properties, the mechanical strengths were exceptionally high, especially at early ages, which is crucial for the stability of sequence layers of printed composites. The tensile strengths were 3.77, 10.5, 13.35, and 18.83 MPa at 1, 3, 7, and 28 days, respectively, and the compressive strengths were 25.1, 68.4, 85.6, and 125.4 MPa at 1, 3, 7, and 28 days, respectively. The test results showed the effectiveness of the fabricated cementitious mixture design method for meeting the requirements for 3D concrete printing applications.

1997 Best Paper Award—Education Committee: A Three-Dimensional Turbine Engine Analysis Compressor Code (TEACC) for Steady-State Inlet Distortion

1998 ◽  
Vol 120 (3) ◽  
pp. 422-430 ◽  
Author(s):  
A. Hale ◽  
W. O’Brien
Keyword(s):  
Three Dimensional ◽  
Simulation Tool ◽  
Source Terms ◽  
Turbine Engine ◽  
Streamline Curvature ◽  
Inlet Distortion ◽  
Blade Row ◽  
Practical Design ◽  
Distorted Region ◽  
Computationally Intensive

The direct approach of modeling the flow between all blade passages for each blade row in the compressor is too computationally intensive for practical design and analysis investigations with inlet distortion. Therefore a new simulation tool called the Turbine Engine Analysis Compressor Code (TEACC) has been developed. TEACC solves the compressible, time-dependent, three-dimensional Euler equations modified to include turbomachinery source terms, which represent the effect of the blades. The source terms are calculated for each blade row by the application of a streamline curvature code. TEACC was validated against experimental data from the transonic NASA rotor, Rotor 1B, for a clean inlet and for an inlet distortion produced by a 90-deg, one-per-revolution distortion screen. TEACC revealed that strong swirl produced by the rotor caused the compressor to increase in loading in the direction of rotor rotation through the distorted region and decrease in loading circumferentially away from the distorted region.

Numerical Simulation of Asymmetric Exhaust Flows Using an Actuator Disc Blade Row Model

2002 ◽  
Author(s):  
Jianjun Liu
Keyword(s):  
Numerical Simulation ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Solution Procedure ◽  
Navier Stokes ◽  
Exhaust Hood ◽  
Navier Stokes Equations ◽  
Multigrid Algorithm ◽  
Blade Row ◽  
Actuator Disc

This paper describes the numerical simulation of the asymmetric exhaust flows by using a 3D viscous flow solver incorporating an actuator disc blade row model. The three dimensional Reynolds-Averaged Navier-Stokes equations are solved by using the TVD Lax-Wendroff scheme. The convergence to a steady state is speeded up by using the V-cycle multigrid algorithm. Turbulence eddy viscosity is estimated by the Baldwin-Lomax model. Multiblock method is applied to cope with the complicated physical domains. Actuator disc model is used to represent a turbine blade row and to achieve the required flow turning and entropy rise across the blade row. The solution procedure and the actuator disc boundary conditions are described. The stream traces in various sections of the exhaust hood are presented to demonstrate the complicity of the flow patterns existing in the exhaust hood.

scholarly journals The development of the Eco-Architecture Concept For Environmentally Responsive In A Tropical Climate

2019 ◽  
Author(s):  
Friyessi
Keyword(s):  
Sustainable Development ◽  
Architectural Design ◽  
Local Development ◽  
Design Method ◽  
Environmentally Friendly ◽  
Tropical Climate ◽  
Design Development ◽  
Design Strategies ◽  
Traditional Architecture ◽  
The Impact

Global warming is the impact of environmental degradation is the increasing average temperature of the earth's surface, including the atmosphere and the ocean. Architecture is the study of the reflection of human settlements with its surroundings so that it has a tendency to adapt to the environment through a variety of approaches in architectural design method is oriented to the environmentally friendly development. Architectural Ecology concept is the concept of building that takes into account the environmental balance of natural and man-made with the main elements, the building and the environment Academically, awareness of architecture students need to be directed to the development process-based ecological both quality and quantity. A discussion of the concept of eco-architecture useful for studying the ecology-based architectural design methods, identify potential and constraints of the tropical climate in the design development strategies that can be systematised as a learning method in the design of sustainable development. Method of discussion by comparing the theoretical analysis method browse through relevant precedent studies to determine the potential and environmental constraints as well as perceptions of the application of the concept of eco Architecture. The results were obtained from the study of theory Architectural Ecology of Heinz Frick and study precedent through the works of Kenneth Yeang and compared with traditional architecture. Summary of the second groove will be used as the draft approaches design strategies in the process of planning and designing environmentally friendly and can be recommended and implemented as a design methodology in learning to achieve sustainable development with an emphasis on quality local development in harmony with nature.

A comparative study of thermal performance in three generations of Iranian residential buildings: Case studies in Csa Gorgan

2020 ◽  
pp. 174425912090624
Author(s):  
Shima Moolavi Sanzighi ◽  
Farzaneh Soflaei ◽  
Mehdi Shokouhian
Keyword(s):  
Thermal Comfort ◽  
Thermal Performance ◽  
Residential Buildings ◽  
Three Dimensional ◽  
Design Parameters ◽  
Design Strategies ◽  
Main Design ◽  
Geometrical Properties ◽  
Architectural Styles ◽  
The Impact

This article focuses on evaluating thermal performance of different types of residential buildings in Mediterranean climate (Csa) of Iran. The aim is to identify the main design parameters in nine research cases, selected from three distinct periods of history with different architectural styles, and evaluating thermal performance of these buildings. To that end, a library study was carried out to identify the most influential passive design strategies and to highlight their impact on thermal comfort and energy efficiency of residential buildings. A field survey was conducted to determine the most common types of average-income houses in Csa climate of Gorgan, Iran, with a historical overview from 19th century to present. Nine buildings were selected to study from three different period of times including the years from 1850 to 1925, 1925 to 1979 and 1979 to present. A three-dimensional numerical model was developed to assess the impact of four main design parameters including orientation, geometrical properties, openings and materials on indoor thermal comfort for each case, using Design Builder commercial software package. The correlation between these design variables and thermal comfort was presented; the results reveal that the contemporary residential buildings are not designed as efficient as traditional houses in this area, in terms of passive energy saving techniques.

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