Preliminary Design of Variable Nozzle Turbines Based on Sensitive Parameters

2020 ◽  
Author(s):  
Sebastian Wittwer ◽  
Ivo Sandor
Keyword(s):  
Engine Performance ◽  
Optimal Solution ◽  
Operating Conditions ◽  
Experimental Results ◽  
Preliminary Design ◽  
Component Level ◽  
Gasoline Engines ◽  
Functional Parameters ◽  
Predictive Quality ◽  
Recent Developments

Abstract Recent developments in turbocharged gasoline engines have established new requirements for the turbine. A simple approach of scaling or optimizing existing turbines on component level might not be sufficient in terms of finding an optimal solution according to the multi-point, multi-disciplinary layout target. In the following paper nondimensional functional parameters are derived from turbomachinery analytics and rated on corresponding values of existing turbine stages. The influence of different parameters on aerodynamic performance is discussed based on CFD results and arranged according to their sensitivity for different engine relevant operating conditions. A metamodel for the preliminary design of variable nozzle turbine stages is derived from DoE (Design of Experiments) based CFD results. It is evaluated regarding its predictive quality on several exemplary turbine stages. Both, CFD and experimental results are therefore used while the experimental results are made up of hot gas stand measurements as well as measurements on engine test bench. Thus, not only the influence of functional parameters can be verified on turbine efficiency characteristics, but beyond that also the predictive quality of engine performance can be assessed.

The Measurement of Component Friction Losses in a Fired Engine: Part 2 — Experimental Results

2005 ◽  
Author(s):  
Riaz A. Mufti ◽  
Martin Priest
Keyword(s):  
Engine Performance ◽  
Cost Effective ◽  
Operating Conditions ◽  
Experimental Results ◽  
Engine Oil ◽  
Sensor Technology ◽  
Component Level ◽  
Component Design ◽  
Engine Part ◽  
Actual Use

Bench testing can provide rapid and cost effective information for developing new lubricants. But there is general agreement that the only satisfactory means of evaluating the behaviour of engine oil is by actual use in engine. Also for detailed analysis of the tribological interaction it is important to analyse the engine performance at the component level. With the help of advance data acquisition system and sensor technology, experimental measurement of friction losses at the component level have been measured at realistic engine operating conditions, using the technique explained in Part 1. This paper describes the outcome of the experimental results at a range of engine operating conditions using mainly SAE 0W20 lubricant and some results from a friction-modified SAE 5W30 lubricant. The results clearly show considerable changes in the percentage contribution of power loss between low and high lubricant temperatures. The change in mode of lubricating regime from boundary to fluid film lubrication can be seen at the component level with increase in engine speed and decrease in lubricant temperature. This system can be used as a powerful tool for screening engine oils, analysing component design, validating friction models and studying the effect of different additives on the performance of each component under realistic operating conditions.

Dynamic Characterization of Tilting Pad Journal Bearings From Component and System Level Testing

2012 ◽  
Author(s):  
Adolfo Delgado ◽  
Mirko Librashi ◽  
Giuseppe Vannini
Keyword(s):  
Stability Analysis ◽  
High Speed ◽  
Dynamic Stiffness ◽  
Operating Conditions ◽  
Logarithmic Decrement ◽  
Experimental Results ◽  
System Level ◽  
Component Level ◽  
Force Coefficients ◽  
Tilting Pad

The dynamic response of a direct lube, 5-pad, rocker-back pivot tilting pad bearing is characterized in a controlled motion (component level) test rig, and in a spin bunker (full system level) using a dummy rotor mounted on two identical bearings. In the component level test, the force coefficients (stiffness, damping, mass) are identified from pseudorandom excitations using a 2-DOF model. N-DOF system including the pad motions has been shown to yield frequency dependent coefficients that warrant the use of asynchronous coefficients for stability analysis in centrifugal compressors. However, experimental results showed that the real part of the dynamic stiffness is well represented as a constant stiffness and mass coefficients while the imaginary part yields a constant damping coefficient (i.e. frequency independent). In the system level test, a dedicated dummy rotor (representative of a high speed centrifugal compressor rotor) is excited by a magnetic shaker throughout a frequency range covering the rotor modes of interest while spinning at constant speed. From the rotor harmonic response the damping of each mode is extracted using a curve-fitting method based on a 1-DOF model for a given set of speeds. The dummy rotor test provides reference values for system logarithmic decrement and further validates the component level test results. The logarithmic decrement prediction using identified bearing force coefficients are in good agreement with the experimental results. In addition, using for prediction identified coefficients in a classical K-C-M or synchronous K-C form yields similar results (within 15%). This indicates that for the given bearing geometry (clearance, offset and size) and operating conditions, synchronously reduced force coefficients are adequate for stability analysis. Comparison of the identified force coefficients with results from commercially available code yielded reasonable agreement on direct coefficients while some discrepancies are highlighted on the cross-coupled coefficients.

Model Adaptation and Nonlinear Model Predictive Control of an Aircraft Engine

2004 ◽  
Author(s):  
Brent J. Brunell ◽  
Daniel E. Viassolo ◽  
Ravi Prasanth
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Nonlinear Model ◽  
Engine Performance ◽  
Aircraft Engine ◽  
Current Control ◽  
Operating Conditions ◽  
Nonlinear Model Predictive Control ◽  
Component Level ◽  
Output Constraints

The performance improvement of constrained nonlinear model predictive control (NMPC) with state and parameter estimation over traditional control architectures is investigated and applied to a model turbofan aircraft engine. Strong nonlinearities are present in turbofan aircraft engines due to the large range of operating conditions and power levels experienced during a typical mission. Also, turbine operation is restricted due to mechanical, aerodynamic, thermal, and flow limitations. Current control methodologies rely strictly on a priori information; therefore they fail to utilize current engine state or health information for reducing conservatism and improving engine performance. NMPC is selected because it depends on a model that can be adapted to the current engine conditions, it can explicitly handle the nonlinearities, both input and output constraints of many variables, and determine the optimal control that will meet the requirements for any engine condition all in a single control formulation. A physics based component level model is developed as the heart of the architecture. The state or health of the engine is determined using a joint state and parameter estimator utilizing extended Kalman filter (EKF) techniques. With the necessary engine information in hand, a constrained NMPC is used to determine the optimal actuator commands. Results regarding steady state performance improvements are presented.

A Gas Turbine Performance Simulation Program and Its Application to an IGCC Gas Turbine

2010 ◽  
Author(s):  
Jong Jun Lee ◽  
Young Sik Kim ◽  
Tong Seop Kim ◽  
Jeong Lak Sohn ◽  
Yong Jin Joo
Keyword(s):  
Gas Turbine ◽  
System Integration ◽  
Gas Turbines ◽  
Engine Performance ◽  
Operating Conditions ◽  
Simulation Program ◽  
Component Level ◽  
Performance Simulation ◽  
Blade Cooling ◽  
Variable Stator

This paper explains a performance simulation program for power generation gas turbines and its application to an IGCC gas turbine. The program has a modular structure and both the stage-level and entire component-level models were adopted. Stage-by-stage calculations were used in the compressor and the turbine. In particular, the compressor module is based on a stage-stacking method and is capable of simulating the effect of variable stator vanes. The combustor model has the capability of dealing with various fuels including syngas. The turbine module is capable of estimating blade cooling performance. The program can be easily extended to other applied cycles such as recuperated and reheated cycles because the program structure is fully modular. The program was verified for simple cycle commercial engines. In addition, the program was applied to the gas turbine in an IGCC plant. Influences of major system integration parameters on the operating conditions of the compressor and turbine as well as on engine performance were analyzed.

Design and Development of an Engine Nozzle Testing Facility

2020 ◽  
Author(s):  
Ramraj H. Sundararaj ◽  
Chandra Sekar ◽  
Rajat Arora ◽  
Abhijit Kushari
Keyword(s):  
Doctoral Students ◽  
Force Measurement ◽  
Engine Performance ◽  
Operating Conditions ◽  
Test Facility ◽  
Complex Geometries ◽  
Component Level ◽  
Turbine Engine ◽  
Successful Design ◽  
Numerous Test

Abstract An engine test facility, capable of being operated with different nozzles, has been developed. The shape of this component has evolved substantially, over the years, from seemingly simple circular geometries to very complex geometries designed to address different requirements. There are numerous test facilities that facilitate an extensive standalone component level testing of these components. However, such testing does not offer an insight into the effect these complex geometries will have on the performance of a gas turbine engine. This facility will serve as a demonstration for graduate and doctoral students, enhancing their understanding of engine performance. The core of the test facility is a single spool turbojet engine from AMT, Netherlands. The engine is instrumented with pressure and temperature measurements at every inter-component location. A conventional intake duct is designed, for measurement of air flow rate. The entire engine is mounted on a 6-axis force measurement device, for measurement of thrust during engine operations. Towards the rear of the engine, a straight duct is attached after the jet pipe, on which any new nozzle can be retrofitted to the engine. To address changes in operating conditions when using different nozzles, the engine is equipped with a suitably designed bleed duct, which is attached onto the jet pipe. The engine, successfully integrated with all the components, has been subjected to multiple tests at different power settings. The first test was done using the baseline engine, operated at various rotor speeds. The next test was done with a custom nozzle having an area ratio of 2, attached to the jet pipe. Owing to the successful design of the components, the engine performance was measured when operated with a smaller area nozzle.

scholarly journals Early Stage Calibration of a Formula SAE Engine 1-D Fluid Dynamic Model with Limited Experimental Data

2020 ◽  
Vol 197 ◽  
pp. 06014
Author(s):  
Francesco Ammendola ◽  
Giovanni Giardiello ◽  
Alfredo Gimelli ◽  
Massimiliano Muccillo ◽  
Davide Riccio ◽  
...  
Keyword(s):  
Experimental Data ◽  
Dynamic Model ◽  
Early Stage ◽  
Fluid Dynamic ◽  
Engine Performance ◽  
Optimal Solution ◽  
Experimental Tests ◽  
Operating Conditions ◽  
Formula Sae ◽  
Engine Model

This work addresses the early stage calibration of a Formula SAE engine 1-D fluid dynamic model starting from limited experimental data. The availability of an engine model since the early stages of the development of a new Formula SAE vehicle allows to carry out preliminary analyses or ECU calibration. A few experimental tests have been executed at wide open throttle and variable engine speed. Then, a 1D thermo-fluid dynamic engine model has been developed starting from the geometry data of the engine. A vector optimization problem has been then solved to calibrate the engine model. In particular, the error minimization between numerical and experimental values of the torque in different engine operating conditions has been set as objective of the optimization process. Finally, starting from the results of the proposed calibration methodology, a decision-making criterion allowed the identification of a single optimal solution within the Pareto optimal front together with the related values for the set of calibration parameters. The results highlight how the proposed calibration procedure could be usefully adopted to set an early stage engine model which could be properly adopted to preliminarily detect the effects of geometric changes or control parameters variations on the main engine performance.

Principles of Thermodynamic Preliminary Design of Civil Turbofan Engines

2009 ◽  
Author(s):  
Vasileios E. Kyritsis ◽  
Pericles Pilidis
Keyword(s):  
Mathematical Problem ◽  
Engine Performance ◽  
Optimal Solution ◽  
Thermodynamic Cycle ◽  
Point Of View ◽  
Design Parameters ◽  
Preliminary Design ◽  
Performance Point ◽  
Component Design ◽  
Direction Component

The design process of a civil turbofan engine is a continuous iteration among a variety of disciplines. From the performance point of view, its main target is the accomplishment of a specified thermodynamic cycle, which is optimised in terms of block fuel for a specified airframe and typical mission, while meeting a variety of multidisciplinary restrictions. Engine performance and component areas are engaged in an interactive collaboration. Performance provides component designers with precious information regarding component operating points and boundary conditions at critical flight conditions and power levels. In the opposite direction, component design is revised to provide performance with the most up-to-date overall component behaviour. Such an iterative process is initiated based on fundamental assumptions regarding the engine architecture, the available proven technology and the customer demands. Scope of the current work is to investigate the effect of engine architecture, component related restrictions and aircraft requirements on engine performance during the preliminary design phase. Given the multi-disciplinary nature of engine design, the conflicting interaction of various design parameters is discussed considering aerodynamic, mechanical and lifing issues. The parameters selected to form the mathematical problem all reflect a level of compromise among the various disciplines. The study aims at justifying the result of an optimal solution, which satisfies the requirements and restrictions set.

Experimental Evaluation of Turbo-Matching Appropriateness of B60J67, B60J68, A58N70 and A58N72 Turbo-Chargers for a Commercial Vehicle Engine

2018 ◽  
Vol 6 (11) ◽  
pp. 71
Author(s):  
Badal Dev Roy ◽  
R. Saravanan
Keyword(s):  
Internal Combustion Engines ◽  
Perfect Match ◽  
Engine Performance ◽  
Operating Conditions ◽  
Data Logger ◽  
Negative Effects ◽  
Road Test ◽  
The Road ◽  
A Charge ◽  
All Speeds

The Turbocharger is a charge booster for internal combustion engines to ensure best engine performance at all speeds and road conditions especially at the higher load.  Random selection of turbocharger may lead to negative effects like surge and choke in the breathing of the engine. Appropriate selection or match of the turbocharger (Turbomatching) is a tedious task and expensive. But perfect match gives many distinguished advantages and it is a one time task per the engine kind. This study focuses to match the turbocharger to desired engine by simulation and on road test. The objective of work is to find the appropriateness of matching of turbochargers with trim 67 (B60J67), trim 68 (B60J68),  trim 70 (A58N70) and trim 72 (A58N72) for the TATA 497 TCIC -BS III engine. In the road-test (data-logger method) the road routes like highway and slope up were considered for evaluation. The operating conditions with respect various speeds, routes and simulated outputs were compared with the help of compressor map.

scholarly journals Optimal Tuner Selection for Kalman Filter-Based Aircraft Engine Performance Estimation

2009 ◽  
Vol 132 (3) ◽  
Author(s):  
Donald L. Simon ◽  
Sanjay Garg
Keyword(s):  
Kalman Filter ◽  
Estimation Error ◽  
Engine Performance ◽  
Aircraft Engine ◽  
Operating Conditions ◽  
Performance Estimation ◽  
Experimental Simulation ◽  
Tuning Parameter ◽  
Estimation Accuracy ◽  
On Line

A linear point design methodology for minimizing the error in on-line Kalman filter-based aircraft engine performance estimation applications is presented. This technique specifically addresses the underdetermined estimation problem, where there are more unknown parameters than available sensor measurements. A systematic approach is applied to produce a model tuning parameter vector of appropriate dimension to enable estimation by a Kalman filter, while minimizing the estimation error in the parameters of interest. Tuning parameter selection is performed using a multivariable iterative search routine that seeks to minimize the theoretical mean-squared estimation error. This paper derives theoretical Kalman filter estimation error bias and variance values at steady-state operating conditions, and presents the tuner selection routine applied to minimize these values. Results from the application of the technique to an aircraft engine simulation are presented and compared with the conventional approach of tuner selection. Experimental simulation results are found to be in agreement with theoretical predictions. The new methodology is shown to yield a significant improvement in on-line engine performance estimation accuracy.

scholarly journals Towards the Hydrogen Economy—A Review of the Parameters That Influence the Efficiency of Alkaline Water Electrolyzers

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3193
Author(s):  
Ana L. Santos ◽  
Maria-João Cebola ◽  
Diogo M. F. Santos
Keyword(s):  
Energy Content ◽  
Water Electrolysis ◽  
High Energy ◽  
Operating Conditions ◽  
Energy Sources ◽  
Alkaline Water Electrolysis ◽  
Alkaline Water ◽  
New Energy ◽  
Recent Developments ◽  
Cell Components

Environmental issues make the quest for better and cleaner energy sources a priority. Worldwide, researchers and companies are continuously working on this matter, taking one of two approaches: either finding new energy sources or improving the efficiency of existing ones. Hydrogen is a well-known energy carrier due to its high energy content, but a somewhat elusive one for being a gas with low molecular weight. This review examines the current electrolysis processes for obtaining hydrogen, with an emphasis on alkaline water electrolysis. This process is far from being new, but research shows that there is still plenty of room for improvement. The efficiency of an electrolyzer mainly relates to the overpotential and resistances in the cell. This work shows that the path to better electrolyzer efficiency is through the optimization of the cell components and operating conditions. Following a brief introduction to the thermodynamics and kinetics of water electrolysis, the most recent developments on several parameters (e.g., electrocatalysts, electrolyte composition, separator, interelectrode distance) are highlighted.

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