scholarly journals Advanced gas turbine performance modelling using response surface methods

2018 ◽  
Vol 122 (1258) ◽  
pp. 1871-1883
Author(s):  
V. Seetharama-Yadiyal ◽  
G.D. Brighenti ◽  
P.K. Zachos
Keyword(s):  
Complex System ◽  
Response Surface ◽  
Pressure Ratio ◽  
Surrogate Models ◽  
Experimental Information ◽  
Design Parameters ◽  
Performance Modelling ◽  
Turbine Performance ◽  
High Pressure Level ◽  
Statistical Metrics

ABSTRACTSurrogate models are widely used for dataset correlation. A popular application very frequently shown in public literature is in the field of engineering design where a large number of design parameters are correlated with performance indices of a complex system based on existing numerical or experimental information. Such an approach allows the identification of the key design parameters and their impact on the system’s performance. The generated surrogate model can become part of wider computational platforms and enable optimisation of the complex system without the need to run expensive simulations.In this paper, a number of design point simulations for a combined gas-steam cycle are used to generate a response surface. The generated response surface correlates a range of cycle’s key design parameters with its thermal efficiency while it also enables identification of the optimum overall pressure ratio and the high pressure level of the raised steam across a range of recuperator effectiveness, pinch temperature difference across the heat recovery steam generator and the pressure at the condenser. The accuracy of a range of surrogate models to capture the design space is evaluated using root mean square statistical metrics.

A Simplified Method for Determining Gas Turbine Performance Parameters Based Upon Available Catalogue Data

2014 ◽  
Author(s):  
Chamila Ranasinghe ◽  
Hina Noor ◽  
Jeevan Jayasuriya
Keyword(s):  
Theoretical Model ◽  
Gas Turbine ◽  
Flue Gas ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Department Of Energy ◽  
Design Parameters ◽  
Learning Platform ◽  
Turbine Performance ◽  
Institute Of Technology

Overall theoretical performance analysis of gas turbines can be conducted by applying design parameters into several thermodynamic theories and equations. However, limited availability of the design parameters will not provide sufficient room for a detailed analysis. Gas turbine manufacturers publish only a limited amount of design/performance data, while important parameters remained hidden and the available information is not sufficiently enough for obtaining a complete gas turbine performance dataset. Five main parameters commonly provided by a gas turbine manufacturer’s catalogues; pressure ratio of the compressor, exhaust mass flow rate, exhaust temperature of flue gas, overall efficiency, and electrical output. A theoretical model developed based on Mathcad software as documented in literature is used to reveal other hidden gas turbine parameters. A similar theoretical model using another solver was developed to obtain a complete dataset by using the available catalogue data with additional assumptions, which correspond to the commercial state of the art. The engineering equation solver (EES) software has been used as a platform to rebuild the theoretical model. As the main development, a graphical user interphase (GUI) has been introduced to the new program with the aim to make it more user friendly. Furthermore on top of obtaining the hidden thermodynamic parameters for the gas turbine, performing flue gas analysis and an exergy analysis has now become possible through this program. The developed EES program is expected to be run in the learning laboratory at the Division of Heat and Power Technology, Department of Energy Technology, Royal Institute of Technology (KTH), Stockholm and finally it is going to be incorporated into CompEdu Learning Platform of the same division.

Automatic Three-Dimensional Optimisation of a Modern Tandem Compressor Vane

2014 ◽  
Author(s):  
R. C. Schlaps ◽  
S. Shahpar ◽  
V. Gümmer
Keyword(s):  
Pressure Ratio ◽  
Three Dimensional ◽  
Trust Region ◽  
Automatic Generation ◽  
Navier Stokes ◽  
Design Parameters ◽  
High Fidelity ◽  
Stall Margin ◽  
Design Choice ◽  
Multipoint Approximation

In order to increase the performance of a modern gas turbine, compressors are required to provide higher pressure ratio and avoid incurring higher losses. The tandem aerofoil has the potential to achieve a higher blade loading in combination with lower losses compared to single vanes. The main reason for this is due to the fact that a new boundary layer is generated on the second blade surface and the turning can be achieved with smaller separation occurring. The lift split between the two vanes with respect to the overall turning is an important design choice. In this paper an automated three-dimensional optimisation of a highly loaded compressor stator is presented. For optimisation a novel methodology based on the Multipoint Approximation Method (MAM) is used. MAM makes use of an automatic design of experiments, response surface modelling and a trust region to represent the design space. The CFD solutions are obtained with the high-fidelity 3D Navier-Stokes solver HYDRA. In order to increase the stage performance the 3D shape of the tandem vane is modified changing both the front and rear aerofoils. Moreover the relative location of the two aerofoils is controlled modifying the axial and tangential relative positions. It is shown that the novel optimisation methodology is able to cope with a large number of design parameters and produce designs which performs better than its single vane counterpart in terms of efficiency and numerical stall margin. One of the key challenges in producing an automatic optimisation process has been the automatic generation of high-fidelity computational meshes. The multi block-structured, high-fidelity meshing tool PADRAM is enhanced to cope with the tandem blade topologies. The wakes of each aerofoil is properly resolved and the interaction and the mixing of the front aerofoil wake and the second tandem vane are adequately resolved.

Optimization of Turbofan Propulsion Cycle Using a Genetic Algorithm

2010 ◽  
Author(s):  
Adel Ghenaiet
Keyword(s):  
Genetic Algorithm ◽  
Fuel Consumption ◽  
Pressure Ratio ◽  
Engine Performance ◽  
Optimization Procedure ◽  
Specific Fuel Consumption ◽  
High Mass ◽  
Design Parameters ◽  
Inlet Temperature ◽  
Simplifying Assumptions

This paper presents an evolutionary approach as the optimization framework to design for the optimal performance of a high-bypass unmixed turbofan to match with the power requirements of a commercial aircraft. The parametric analysis had the objective to highlight the effects of the principal design parameters on the propulsive performance in terms of specific fuel consumption and specific thrust. The design optimization procedure based on the genetic algorithm PIKAIA coupled to the developed engine performance analyzer (on-design and off-design) aimed at finding the propulsion cycle parameters minimizing the specific fuel consumption, while meeting the required thrusts in cruise and takeoff and the restrictions of temperatures limits, engine size and weight as well as pollutants emissions. This methodology does not use engine components’ maps and operates on simplifying assumptions which are satisfying the conceptual or early design stages. The predefined requirements and design constraints have resulted in an engine with high mass flow rate, bypass ratio and overall pressure ratio and a moderate turbine inlet temperature. In general, the optimized engine is fairly comparable with available engines of equivalent power range.

Performance analysis of wave rotor based on response surface optimization method

2021 ◽  
pp. 1-18
Author(s):  
Peiqi Liu ◽  
Mingyu Feng ◽  
Xinyu Liu ◽  
Haitao Wang ◽  
Dapeng Hu
Keyword(s):  
Entropy Production ◽  
Response Surface ◽  
Relative Velocity ◽  
Pressure Ratio ◽  
Pressure Fluctuations ◽  
Optimization Method ◽  
Wave Rotor ◽  
Compression Waves ◽  
Isentropic Expansion ◽  
Response Surface Optimization

Abstract An optimized wave rotor refrigerator (WRR) that can convert part of the expansion work into shaft work to improve the refrigeration performance is obtained by optimization method. Bézier curve is used to establish a two-dimensional simplified model, and response surface method and NLPQL optimization algorithm are used to search for the optimal wave rotor structure. The results show that the optimized wave rotor shape is rear back bending. Compared with original rotor, the isentropic expansion efficiency of the optimized rotor is higher under different pressure ratios and relative velocity, and changes more gently under different pressure ratios. Moreover, the expansion power of the optimized rotor is mainly converted into shaft powder, while the pressure energy and thermal energy increase at the hot end is relatively small. The pressure fluctuations on the inlet and outlet sides of the optimized rotor are smoother, and the compression waves that are constantly reflected during the low-temperature exhaust stage have a smaller intensity, which helps to improve the performance of WRR. The optimized rotor can significantly reduce the entropy production in the refrigeration process, especially the entropy production by velocity gradients. When the pressure ratio is 2.0 and relative velocity is 23 m/s, the isentropic expansion efficiency increases from 56.8% of the original rotor to 62.08% of the optimized rotor.

Numerical Efforts of Aerodynamic Re-Design in a Single-Stage Transonic Axial Compressor: Part 1 — Stator Design

2017 ◽  
Author(s):  
Justin (Jongsik) Oh
Keyword(s):  
Pressure Ratio ◽  
Axial Compressor ◽  
Axial Flow ◽  
Single Stage ◽  
Design Flow ◽  
Design Parameters ◽  
Original Design ◽  
Circular Arc ◽  
Surge Margin ◽  
Flow Compressor

In many aerodynamic design parameters for the axial-flow compressor, three variables of tailored blading, blade lean and sweep were considered in the re-design efforts of a transonic single stage which had been designed in 1960’s NASA public domains. As Part 1, the re-design was limited to the stator vane only. For the original MCA (Multiple Circular Arc) blading, which had been applied at all radii, the CDA (Controlled Diffusion Airfoil) blading was introduced at midspan as the first variant, and the endwalls of hub and casing (or tip) were replaced with the DCA (Double Circular Arc) blading for the second variant. Aerodynamic performance was predicted through a series of CFD analysis at design speed, and the best aerodynamic improvement, in terms of pressure ratio/efficiency and operability, was found in the first variant of tailored blading. It was selected as a baseline for the next design efforts with blade lean, sweep and both combined. Among 12 variants, a case of positively and mildly leaned blades was found the most attractive one, relative to the original design, providing benefits of an 1.0% increase of pressure ratio at design flow, an 1.7% increase of efficiency at design flow, a 10.5% increase of the surge margin and a 32.3% increase of the choke margin.

Numerical Analysis of Deposits and Corrosion Influence on a Centrifugal Compressor Performance

2012 ◽  
Author(s):  
Mohammad R. Aligoodarz ◽  
Mohammad Reza Soleimani Tehrani ◽  
Hadi Karrabi ◽  
Mohammad R. Roshani
Keyword(s):  
Numerical Modeling ◽  
Centrifugal Compressor ◽  
Pressure Ratio ◽  
Mechanical Damage ◽  
3D Numerical Modeling ◽  
Compressor Blades ◽  
Turbine Performance ◽  
Common Causes ◽  
Sst Turbulence Model ◽  
Compressor Performance

Turbo machineries including compressors performance degrades over the period of operation and deviates from design levels due to causes including dust entrance into the compressor, blades mechanical damage, erosion and corrosion. These lead to reduction in compressor performance, efficiency and pressure ratio. Subsequently gas turbine performance is affected since their operation sate is correlated. In this study the numerical investigation of common causes that determine geometric characteristics of a 2-stage centrifugal compressor running in a gas station, including blades fouling and corrosion is performed. 3D Numerical modeling is implemented along with utilization of Shear Stress Transport (SST) turbulence model and independency from the grids is verified.

Investigation on a Blockerless Cascade Thrust Reverser System Based on Response Surface Method

2018 ◽  
Author(s):  
Li Zhou ◽  
Zhanxue Wang ◽  
Jingwei Shi ◽  
Xiaobo Zhang
Keyword(s):  
High Pressure ◽  
Secondary Flow ◽  
Response Surface ◽  
Response Surface Method ◽  
Interaction Effect ◽  
Pressure Ratio ◽  
Surface Method ◽  
Thrust Reverser ◽  
Reverse Thrust ◽  
Secondary Injection

The blockerless cascade thrust reverser is one of the innovative thrust reverser systems, which replaces the traditionally mechanical blocker door with the aerodynamic blocker door by high-pressure secondary injection, thus significantly reduces the nacelle weight and the complexity of the actuator, and especially suitable for high-bypass-ratio turbofan engine. In order to obtain the optimum performance of a blockerless cascade thrust reverser system and provide the guidance for the design of the blockerless cascade thrust reverser system, a blockerless cascade thrust reverser system was studied in this paper based on the Response Surface Method (RSM), focusing on the effect of different geometric and aerodynamic parameters on the thrust reverser performance. Results show that the secondary injection with high pressure forms the blockage effect to the fan flow, then forces the fan flow to deflect and discharge from the cascade window, realizing the reverse thrust. The thrust reverser performance is mainly affected by fan pressure ratio (FPR), secondary flow pressure ratio (SPR), secondary injection position (Xjet), secondary injection angle (αjet) and cascade installation angle (β), and the dominated factors are FPR, SPR and Xjet. According to the obtained response equation of the thrust reverser performance, the relationship between reverse thrust efficiency and various parameters are clearly described, and performance of thrust reverser can be quickly evaluated. Significant interaction effects exist between different two factors, which must be taken into consideration in the design process of the blockerless cascade thrust reverser system, especially for the interaction effect between FPR and Xjet, interaction effect between FPR and β. Optimization design with objective of maximum reverse thrust was carried out to determine the best parameter settings, and reverse thrust ratio ηTrev of 60% is achieved under the constraint of the secondary flow ratio.

Semi-controlled experiment plans for improved mechanical engineering designs

2000 ◽  
Vol 214 (2) ◽  
pp. 95-105 ◽  
Author(s):  
C J Sexton ◽  
W Dunsmore ◽  
S M Lewis ◽  
C P Please ◽  
G Pitts
Keyword(s):  
Response Surface ◽  
Special Interest ◽  
Design Parameter ◽  
Orthogonal Arrays ◽  
Small Sample ◽  
Design Parameters ◽  
Hydraulic Pump ◽  
Parameter Region ◽  
Mechanical Products ◽  
Engineering Designs

The use of planned experiments to improve designs is considered for situations where standard plans, such as orthogonal arrays or response surface plans, are impractical. An approach is described that is of special interest to the design of mechanical products where it is expensive to make prototype components to specified dimensions, and only a given small sample of components of diffiering dimensions is available. The plan for the experiment must then make the best use of the available components by determining an assembly that will most efficiently explore the expected design parameter region where the design parameters may be derived from the component dimensions. In contrast to conventional methods, the resulting experiment is semi-controlled, rather than fully controlled, as the component dimensions cannot be chosen but the assembly can. An algorithm for finding such plans is described and an example of its implementation in improving the design of an hydraulic pump is presented. The method extends to studies involving some components whose dimensions cannot be designated and hence are obtained from a small sample, and other components that are easily and cheaply constructed to prescribed dimensions. This results in a combination of semi-controlled and fully controlled factors. Efficient plans for such experiments are described and results from their application in practice are discussed.

Dry Sliding Wear Behaviour of Magnesium nanocomposites using Response Surface Methodology

2021 ◽  
pp. 1-18
Author(s):  
Kartheesan S ◽  
B. Shahul hamid Khan ◽  
M Kamaraj ◽  
Manoj Gupta ◽  
Sravya Tekumalla
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Sliding Wear ◽  
Wear Behaviour ◽  
Design Parameters ◽  
Dry Sliding Wear ◽  
Wear Loss ◽  
Sliding Velocity ◽  
Sliding Distance ◽  
Sliding Wear Behaviour

Abstract In this study, a pure magnesium material reinforced with 0.5, 1, 1.5, and 2 weight % of CaO was prepared through disintegrated melt deposition technique. Nanocomposites were investigated for their sliding wear behaviour in dry condition at room temperature. Amount of CaO, Load, sliding distance, and Sliding velocity were selected as input design parameters at their five-level in central composite design using Minitab 18.1 statistical software. The influence of design parameters on wear loss is reported through the Response Surface Methodology (RSM). ANOVA was used to confirm the soundness of the developed regression equation. The results indicate the contribution of linear, quadratic, and interaction terms of design parameters on response. 3D response surface and 2D contour plots are indicated the interaction effect. The result shows that an increase in sliding velocity contributes to a decrease in the wear loss of the composites because of the emergence of protective oxidative layer at the surfaces of the pins, which is confirmed through FESEM and EDAX analysis of the pin surfaces. Wear loss of the material decreased as amount of CaO increased. The ANOVA analysis concluded that the sliding distance and load contribute significantly to wear loss of the composites and their percentage of contribution is 64.02 % and 3.69%.

Theoretical and Experimental Study on the Ultimate Strength of Corrugated Bulkheads

1997 ◽  
Vol 41 (04) ◽  
pp. 301-317
Author(s):  
Jeom K. Paik ◽  
Anil K. Thayamballi ◽  
Min S. Chun
Keyword(s):  
Ultimate Strength ◽  
Lateral Pressure ◽  
Limit State ◽  
Plate Thickness ◽  
Experimental Information ◽  
Design Guidelines ◽  
Design Parameters ◽  
Collapse Mechanism ◽  
Ultimate Limit State ◽  
Analytical Formulation

The objectives of the present study are to obtain experimental data on collapse strength of steel corrugated bulkhead models and also to develop a simple analytical formulation for ultimate strength useful in the design of corrugated bulkheads under static lateral pressure. Collapse tests on nine mild steel corrugated bulkhead models having five bays of corrugations are carried out, varying the corrugation angle, the plate thickness and the type of loading (axial compression and/or lateral pressure). Using the test data, the characteristics of the collapse mechanism for corrugated bulkheads are investigated. For purposes of rapid first cut estimates of strength, a new and simple analytical formulation for predicting the ultimate strength of corrugated bulkheads under hydrostatic pressure is derived based on an assumed stress distribution over the corrugation cross section at the ultimate limit state. The modeling error associated with the new formulation is established by comparing its predictions with the experimental results. The development of ultimate strength based design guidelines and the effect of design parameters such as the corrugation angle on ultimate strength of a corrugated bulkhead are then discussed. All experimental information and strength data are tabulated, which is a benefit in itself.

Sign in / Sign up

Export Citation Format

Share Document