Pre-Test Evaluation of Probe Configuration Errors

2019 ◽  
Author(s):  
John Gillespie ◽  
Dustin Frohnapfel ◽  
Walter O’Brien
Keyword(s):  
Total Pressure ◽  
Flow Property ◽  
Test Time ◽  
Test Evaluation ◽  
Flow Profile ◽  
Flow Distortion ◽  
Turbine Engine ◽  
Point To Point ◽  
The Cost ◽  
The Impact

Abstract Rake probes are commonly used in turbomachinery applications to measure distorted inlet flows, including both pressure and swirl distortions. An especially common configuration is the 40 probe rake array, consisting of eight identical arms equally spaced circumferentially around the inlet, each arm having five sensing locations spaced along centers of equal area. By measuring many locations simultaneously, rake probes have the advantage of expedited data collection when compared to traversing probes. However, this reduction in test time comes at the cost of rigid geometry with limited measurement locations. As a result, it is possible for rake probes to miss or exaggerate significant areas of the flow profile, such as large gradients or small features, based on the fixed location of the probe and the particular details of the distortion. The purpose of this paper is to demonstrate a procedure that can be used to evaluate the ability of any desired probe configuration (40 probe rake or otherwise) to sufficiently and accurately measure a non-uniform flow profile. Results of this procedure for a range of profiles and probe configurations are also presented. In order to accurately determine the impact of discrete sampling on the results, two broad sets of data were generated numerically and analyzed. The first set consists of four fundamental total pressure distortions: once-per-rev circumferential, twice-per-rev circumferential, hub radial, and tip radial. The second set consists of three realistic turbofan distortion patterns: two analytic (though not fundamental) profiles, and one generated from S-duct computational results. For all investigated patterns, Radial Distortion Intensity and Circumferential Distortion Intensity are calculated in the manner described by ARP 1420, a guideline issued by the S-16 Turbine Engine Inlet Flow Distortion Committee for measuring total pressure distortions in turbomachinery. Additionally, interpolated total pressure contours are generated for each measurement configuration. These were then used to make point-to-point comparisons between the actual and estimated data. While total pressure distortion was used as the variable of interest for the majority of this paper, the conclusions may be applied to swirl, temperature, or any other flow property measured using a probe rake or traversing probe.

A Fast Gas Turbine Engine Performance Analysis Tool Able to Capture Three Dimensional Effects

2007 ◽  
Author(s):  
Ioannis Templalexis ◽  
Pericles Pilidis ◽  
Vassilios Pachidis ◽  
Petros Kotsiopoulos
Keyword(s):  
Three Dimensional ◽  
Axial Flow ◽  
Engine Performance ◽  
Flow Simulation ◽  
Simulation Method ◽  
Flow Profile ◽  
Flow Distortion ◽  
Performance Simulation ◽  
Turbine Engine ◽  
The Impact

Given the current level of computational resources that are readily available, three dimensional (3-D) gas turbine engine performance simulation remains extremely time consuming. The current paper presents a synthesis of existing flow simulation methods coupled together in the form of a new software package. The software is able to assess the impact of a 3-D flow profile at the intake inlet on engine performance, demanding relatively low computational resources. More precisely four flow simulation techniques are employed, represented respectively by four individual stand alone software sub-modules. 3-D Vortex Lattice Method (VLM) is used to simulate the intake flow. Subsequently the intake outlet 3-D flow profile is decomposed into a radial and a circumferential component. For the compressor performance simulation, that receives those components as inlet boundary conditions, a two dimensional (2-D) Streamline Curvature (SLC) simulation method coupled with an extended parallel compressor model is used. SLC addresses the impact of the radial flow distortion, whereas the extended parallel compressor model examines the impact of circumferential flow distortion on engine performance. The results of the above analysis are stored into an intake-compressor performance characteristic map, which is then fed into a zero dimensional (0-D) performance simulation tool in order to evaluate the overall impact of the intake inlet distorted flow on engine performance. The paper is divided into two major sections. The first one presents the individual flow simulation techniques, together with the corresponding software modules. A short summary of each method is given first and then the software module is described, followed by brief comments on the validation results that have been already published. The section in concluded by the description of the synthesized software. The second major section deals with the application of the synthesized simulation method on a turbojet engine. A generic turbojet engine has been chosen mounted behind a generic intake, given the lack of relevant experimental results. The engine has a four stage axial flow compressor driven by a single stage axial flow turbine, followed by a converging nozzle. 3-D total pressure profiles were imposed at the intake inlet and several comparative graphs of engine’s performance parameters between “clean” and distorted inlet flow conditions are given. The paper is concluded with a discussion on software’s abilities and weaknesses as well as on its potential future expansion.

Aircraft Turbine Engine Emissions and the Possibilities for Control

1972 ◽  
Author(s):  
Charles Gray ◽  
G. D. Kittredge
Keyword(s):  
Air Quality ◽  
Environmental Protection Agency ◽  
Cost Effective ◽  
Technology Study ◽  
Aircraft Emissions ◽  
Engine Emissions ◽  
Turbine Engine ◽  
Time Requirements ◽  
The Cost ◽  
The Impact

The Environmental Protection Agency has completed a study of the impact of aircraft emissions on air quality and a study of the technological feasibility of controlling aircraft emissions including an analysis of the cost and time requirements of the various control approaches. The air quality study has determined the need for aircraft emission standards, and the control technology study has determined that control is feasible and cost effective given adequate development time.

The Effect of Inlet Flow Distortion on Performance of a Micro-Jet Engine: Part 2 — Engine Tests

2012 ◽  
Author(s):  
A. Naseri ◽  
M. Boroomand ◽  
A. M. Tousi ◽  
A. R. Alihosseini
Keyword(s):  
Steady State ◽  
Total Pressure ◽  
Engine Performance ◽  
Flow Distortion ◽  
Inlet Flow ◽  
Jet Engine ◽  
Turbine Engine ◽  
Air Jet ◽  
Engine Part ◽  
Inlet Flow Distortion

This paper concerns investigating effect of inlet flow distortion on performance of a micro-jet engine. An experimental study has been carried out to determine how the steady state inlet total-pressure distortion affects the performance of a micro gas turbine engine. An inlet simulator is designed and developed to produce and measure distortion patterns at the engine inlet. An Air Jet Distortion Generator is used to produce non-uniform flow patterns and total pressure probes are implemented to measure steady state total pressure distribution at the engine face. A set of wind tunnel tests has been performed to confirm the fidelity of distortion generator and measuring devices. The engine got exposed to inlet flow with 60-degree, 120-degree, and 180-degree circumferential distortion patterns with different distortion intensities and the engine performance have been measured and compared with that of clean inlet flow. Results indicate that engine performance can be affected significantly facing with intense inlet distortions.

scholarly journals JET ENGINE INLET DISTORTION SCREEN AND DESCRIPTOR EVALUATION

2017 ◽  
Vol 57 (1) ◽  
pp. 22-31 ◽  
Author(s):  
Jiří Pečinka ◽  
Gabriel Thomas Bugajski ◽  
Petr Kmoch ◽  
Adolf Jílek
Keyword(s):  
Total Pressure ◽  
Basic Flow ◽  
Interface Plane ◽  
Inlet Channel ◽  
Flow Distortion ◽  
Turbine Engine ◽  
Inlet Distortion ◽  
Mass Flow Rates ◽  
Total Temperature ◽  
The University

Total pressure distortion is one of the three basic flow distortions (total pressure, total temperature and swirl distortion) that might appear at the inlet of a gas turbine engine (GTE) during operation. Different numerical parameters are used for assessing the total pressure distortion intensity and extent. These summary descriptors are based on the distribution of total pressure in the aerodynamic interface plane. There are two descriptors largely spread around the world, however, three or four others are still in use and can be found in current references. The staff at the University of Defence decided to compare the most common descriptors using basic flow distortion patterns in order to select the most appropriate descriptor for future department research. The most common descriptors were identified based on their prevalence in widely accessible publications. The construction and use of these descriptors are reviewed in the paper. Subsequently, they are applied to radial, angular, and combined distortion patterns of different intensities and with varied mass flow rates. The tests were performed on a specially designed test bench using an electrically driven standalone industrial centrifugal compressor, sucking air through the inlet of a TJ100 small turbojet engine. Distortion screens were placed into the inlet channel to create the desired total pressure distortions. Of the three basic distortions, only the total pressure distortion descriptors were evaluated. However, both total and static pressures were collected using a multi probe rotational measurement system.

The Effect of Inlet Flow Distortion on Performance of a Micro-Jet Engine: Part 1 — Development of an Inlet Simulator

2012 ◽  
Author(s):  
A. Naseri ◽  
M. Boroomand ◽  
A. M. Tousi
Keyword(s):  
Wind Tunnel ◽  
Total Pressure ◽  
Engine Performance ◽  
Flow Distortion ◽  
Inlet Flow ◽  
Jet Engine ◽  
Wind Tunnel Tests ◽  
Turbine Engine ◽  
Air Jet ◽  
Air Supply

This paper represents the development of an inlet simulator to produce and measure steady state total-pressure distortion at the inlet of a micro-jet engine. Different methods of distortion generation and engine testing are discussed and the developed system is described. The developed inlet simulator device consists of a direct connecting air supply duct, a distortion generator unit inside the duct ahead of the engine inlet, and a matrix of total pressure probes at the end of the duct and close to engine entry. An Air Jet Distortion Generator is designed and developed to produce desired distortion patterns at the engine face. A series of wind tunnel tests has been carried out to verify the ability of the system to simulate various inlet flow conditions. Circumferential patterns with 60, 120 and 180 degree distorted zones with different distortion intensities were produced during wind tunnel tests. Measured distortion patterns are represented and the proper operation of the system in wind tunnel is discussed and proved. The inlet simulator then get installed on a micro gas turbine engine and distortion patterns has been produced and measured at the engine inlet during engine performance tests. Measured patterns at the engine inlet and the engine responses are represented.

Demonstrating Nutrient Cost Gradients: A Brooklyn Case Study

2014 ◽  
Vol 84 (5-6) ◽  
pp. 244-251 ◽  
Author(s):  
Robert J. Karp ◽  
Gary Wong ◽  
Marguerite Orsi
Keyword(s):  
Low Income ◽  
Energy Content ◽  
Food Selection ◽  
The United States ◽  
United States Department ◽  
Micronutrient Deficiencies ◽  
Caloric Density ◽  
Low Income Families ◽  
The Cost ◽  
The Impact

Abstract. Introduction: Foods dense in micronutrients are generally more expensive than those with higher energy content. These cost-differentials may put low-income families at risk of diminished micronutrient intake. Objectives: We sought to determine differences in the cost for iron, folate, and choline in foods available for purchase in a low-income community when assessed for energy content and serving size. Methods: Sixty-nine foods listed in the menu plans provided by the United States Department of Agriculture (USDA) for low-income families were considered, in 10 domains. The cost and micronutrient content for-energy and per-serving of these foods were determined for the three micronutrients. Exact Kruskal-Wallis tests were used for comparisons of energy costs; Spearman rho tests for comparisons of micronutrient content. Ninety families were interviewed in a pediatric clinic to assess the impact of food cost on food selection. Results: Significant differences between domains were shown for energy density with both cost-for-energy (p < 0.001) and cost-per-serving (p < 0.05) comparisons. All three micronutrient contents were significantly correlated with cost-for-energy (p < 0.01). Both iron and choline contents were significantly correlated with cost-per-serving (p < 0.05). Of the 90 families, 38 (42 %) worried about food costs; 40 (44 %) had chosen foods of high caloric density in response to that fear, and 29 of 40 families experiencing both worry and making such food selection. Conclusion: Adjustments to USDA meal plans using cost-for-energy analysis showed differentials for both energy and micronutrients. These differentials were reduced using cost-per-serving analysis, but were not eliminated. A substantial proportion of low-income families are vulnerable to micronutrient deficiencies.

TRANSFER FİYATLAMA UYGULAMASININ İŞLETME PERFORMANSINA ETKİSİ VE VERGİSEL AÇIDAN DEĞERLENDİRİLMESİ

2014 ◽  
Vol 1 (2) ◽  
pp. 187
Author(s):  
Serdar KUZU
Keyword(s):  
Business Performance ◽  
Transfer Pricing ◽  
Tax Law ◽  
Economic Activities ◽  
Tax System ◽  
Goods And Services ◽  
Tax Legislation ◽  
International Transactions ◽  
The Cost ◽  
The Impact

The size of international trade continues to extend rapidly from day to day as a result of the globalization process. This situation causes an increase in the economic activities of businesses in the trading area. One of the main objectives of the cost system applied in businesses is to be able to monitor the competitors and the changes that can be occured as a result of the developments in the sector. Thus, making cost accounting that is proper according to IAS / IFRS and tax legislation has become one of the strategic targets of the companies in most countries. In this respect, businesses should form their cost and pricing systems according to new regulations. Transfer pricing practice is usefull in setting the most proper price for goods that are subject to the transaction, in evaluating the performance of the responsibility centers of business, and in determining if the inter-departmental pricing system is consistent with targets of the business. The taxing powers of different countries and also the taxing powers of different institutions in a country did not overlap. Because of this reason, bringing new regulations to the tax system has become essential. The transfer pricing practice that has been incorporated into the Turkish Tax System is one of the these regulations. The transfer pricing practice which includes national and international transactions has been included in the Corporate Tax Law and Income Tax Law. The aim of this study is to analyse the impact of goods and services transfer that will occur between departments of businesses on the responsibility center and business performance, and also the impact of transfer pricing practice on the business performance on the basis of tax-related matters. As a result of the study, it can be said that transfer pricing practice has an impact on business performance in terms of both price and tax-related matters.

Assessing the Impact of the Inlet Total Pressure Distortion on the Turbofan Thrust

2018 ◽  
pp. 19-30
Author(s):  
Yu. A. Ezrokhi ◽  
E. A. Khoreva
Keyword(s):  
Total Pressure ◽  
External Compression ◽  
Average Value ◽  
Inlet Distortion ◽  
Air Inlet ◽  
Engine Thrust ◽  
Relative Value ◽  
Main Effect ◽  
Pressure Recovery Factor ◽  
The Impact

The paper considers techniques to develop a mathematical model using a method of «parallel compressors». The model is intended to estimate the impact of the air inlet distortion on the primary parameters of the aero-engine.  The paper presents rated estimation results in the context of twin spool turbofan design for two typical cruiser modes of flight of the supersonic passenger jet. In estimation the base values σbase and the average values of the inlet ram recovery σave remained invariable. Thus, parametrical calculations were performed for each chosen relative value of the area of low-pressure region.The paper shows that an impact degree of the inlet distortion on the engine thrust for two modes under consideration is essentially different. In other words, if in the subsonic mode the impact assessment can be confined only to taking into account the influence of decreasing average values of the inlet total pressure, the use of such an assumption in the supersonic cruiser mode may result in considerable errors.With invariable values of the pressure recovery factor at the engine intake, which correspond to the speed of flight for a typical air inlet of external compression σbase, and average value σave, a parameter Δσuneven  has the main effect on the engine thrust, and degree of this effect essentially depends on a difference between σave and σbase values.

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