Optimization and Simulation of a CFR Engine Fueled by Dilute Anode Tail-Gas

2020 ◽  
Author(s):  
Alexander Balu ◽  
Miguel Castro ◽  
Geet Padhi ◽  
Todd Bandhauer ◽  
Bret Windom ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Response Surface ◽  
Response Surface Method ◽  
Operating Conditions ◽  
Computational Time ◽  
Boost Pressure ◽  
Engine Operation ◽  
Dewpoint Temperature ◽  
Surface Method ◽  
Method Optimization

Abstract Recent innovations in Metal Supported Solid Oxide Fuel Cells (MS-SOFC) have increased the longevity and reliability of fuel cells. These innovations drive the desire to create power generating systems that combine different ways of extracting power from a fuel to increase overall thermal efficiency. This investigation assesses the feasibility of operating an internal combustion engine with the anode tail-gas, which is a blend of H2, CO, CO2, H2O, and CH4, exhausted by a MS-SOFC. This engine would be used to support fuel cell balance of plant equipment and produce excess electrical power. Four variations of the expected anode tail-gas blends were determined by varying the dewpoint temperature of the fuel. Gas blends are tested by combining separate flows of each constituent, and combustion is tested using a Cooperative Fuel Research (CFR) engine. Compression ratio, spark timing, inlet manifold temperature, and boost pressure were used to obtain optimal operating conditions. Stable engine operation was obtained on all test blends. A combination of computational fluid dynamics (CFD) and analysis of chemical species and reaction mechanisms is used to develop an engine and combustion model. This model allows for further investigation into anode tail-gas combustion characteristics. Response Surface Method Optimization was used to experimentally optimize operating parameters and determine the maximum achievable efficiency utilizing the CFR engine. All test blends with H2O produced power in the engine although the blend with the most water content caused operational problems with the CFR engine test stand, including large amounts of water entering the oil system. Three chemical kinetic mechanisms were investigated that had the correct species for simulating the fuel with a low number of reactions to facilitate low computational time: San Diego (SD), GRI and Gallway 2017 (NUIG) mechanism. Out of these four mechanisms, the NUIG mechanism results fit the CFR engine experimental data best. Response Surface Method Optimization was performed on the most viable test blends, the steam injections blends at 40°C and 90°C fuel dewpoint temperature. During optimization the 40°C dewpoint temperature blend brake efficiency increased from 20% to 21.6%, and the 90°C dewpoint temperature blend brake efficiency increased from 17% to 22.3%.

Response Surface Method Optimization of Uniform and Axially Segmented Duct Acoustics Liners

2006 ◽  
Vol 43 (4) ◽  
pp. 1089-1102 ◽  
Author(s):  
L. Lafronza ◽  
A. McAlpine ◽  
A. J. Keane ◽  
R. J. Astley
Keyword(s):  
Response Surface ◽  
Response Surface Method ◽  
Duct Acoustics ◽  
Surface Method ◽  
Method Optimization

RELIABILITY DESIGN EVALUATION AND OPTIMIZATION OF A NITROGEN GAS BOTTLE USING RESPONSE SURFACE METHOD

2010 ◽  
Vol 17 (02) ◽  
pp. 119-132 ◽  
Author(s):  
P. BHATTACHARJEE ◽  
K. RAMESH KUMAR ◽  
T. A. JANARDHAN REDDY
Keyword(s):  
Design Optimization ◽  
Response Surface ◽  
Response Surface Method ◽  
Structural Reliability ◽  
Operating Conditions ◽  
Optimization Under Uncertainty ◽  
Reliability Based Design Optimization ◽  
Nitrogen Gas ◽  
Reliability Based Design ◽  
Surface Method

Optimization of any aerospace product results in increasing payload capacity of space vehicles. Essentially weight, volume and cost are the main constraints. Design optimization studies for aerospace system are increasingly gaining importance. The problem of optimum design under uncertainty has been formulated as reliability-based design optimization. The reliability based optimization, which includes robustness requirements leads to multi-objective optimization under uncertainty. In this paper Reliability, based design optimization study is carried out under linear constraint optimization to minimize the weight of a nitrogen gas bottle with specified target reliability. Response surface method considering full factorial experiment is used to establish multiple regression equation for induced hoop stress and maximum strain. Necessary data pertaining to design, manufacturing and operating conditions are collected systematically for variability study. Structural reliability is evaluated using Advanced First-Order Second-Moment Method (AFOSM). Finally, optimization formulation established and it has been discussed in this paper.

Reliability-Based Design Optimization Using Response Surface Method With Prediction Interval Estimation

2008 ◽  
Vol 130 (12) ◽  
Author(s):  
Chwail Kim ◽  
K. K. Choi
Keyword(s):  
Design Optimization ◽  
Response Surface ◽  
Response Surface Method ◽  
Prediction Interval ◽  
Upper And Lower Bounds ◽  
Computational Time ◽  
Engineering System ◽  
Reliability Based Design Optimization ◽  
Reliability Based Design ◽  
Surface Method

Since variances in the input variables of the engineering system cause subsequent variances in the product output performance, reliability-based design optimization (RBDO) is getting much attention recently. However, RBDO requires expensive computational time. Therefore, the response surface method is often used for computational efficiency in solving RBDO problems. A method to estimate the effect of the response surface error on the RBDO result is developed in this paper. The effect of the error is expressed in terms of the prediction interval, which is utilized as the error metric for the response surface used for RBDO. The prediction interval provides upper and lower bounds for the confidence level that the design engineer specified. Using the prediction interval of the response surface, the upper and lower limits of the reliability are computed. The lower limit of reliability is compared with the target reliability to obtain a conservative optimum design and thus safeguard against the inaccuracy of the response surface. On the other hand, in order to avoid obtaining a design that is too conservative, the developed method also constrains the upper limit of the reliability in the design optimization process. The proposed procedure is combined with an adaptive sampling strategy to refine the response surface. Numerical examples show the usefulness and the efficiency of the proposed method.

Fan Blade Tip Aerodynamics With Realistic Operational Casing Geometries and Clearances

2017 ◽  
Author(s):  
Alistair John ◽  
Ning Qin ◽  
Shahrokh Shahpar
Keyword(s):  
Response Surface ◽  
Response Surface Method ◽  
Leading Edge ◽  
Parametric Model ◽  
Engine Operation ◽  
Detailed Understanding ◽  
Surface Method ◽  
Flow Features ◽  
Blade Tip ◽  
Fan Blade

During engine operation fan casing abradable liners are worn by the blade tip, resulting in the formation of trenches. This paper investigates the influence of these trenches on the fan blade tip aerodynamics. A detailed understanding of the tip flow features for the fan blade under investigation is developed. A parametric model is then used to model trenches in the casing above the blade tip. It is shown that increasing clearance via a trench reduces performance by less than increasing clearance through cropping the blade tip. A response surface method is then used to generate a model that can predict fan efficiency for a given set of clearance and trench parameters. It is shown that the efficiency sensitivity to clearance is greater for cropped tips than trenches, and is biased towards the leading edge for cropped tips, and the trailing edge for trenches.

Application of the Response Surface Method to the Tribological Analysis of a Medium-Carbon Steel Under Mild-Oxidational Wear

1999 ◽  
Vol 121 (1) ◽  
pp. 185-197 ◽  
Author(s):  
Chau Chang Chou ◽  
Jen Fin Lin
Keyword(s):  
Experimental Data ◽  
Wear Rate ◽  
Response Surface ◽  
Response Surface Method ◽  
Applied Load ◽  
Operating Conditions ◽  
Contact Temperature ◽  
Rate Parameter ◽  
Sliding Speed ◽  
Surface Method

Instead of using the conventional oxidation theory to depict a disk’s wear rate as a function of contact temperature, the response surface method (RSM) is herein introduced to relieve the one-factor-at-a-time defect in portraying tribological characteristics. By means of a central composite design technique, fewer operating conditions are needed to establish expressions for the wear rate parameter, the contact temperature and the friction coefficient as a function of sliding speed and applied load. A second degree polynomial was used to represent a curved surface which fits the experimental data. In addition to results for the designated operating conditions, wear rate parameters and contact temperatures obtained from the polynomials were compared with the experimental results. The activation energy in the wear rate expression can be derived from a function of sliding speed, applied load, and contact temperature. The experimental data for the wear rate parameter can be described by smooth curves, instead of two different straight lines in two temperature divisions.

scholarly journals Coupled CFD-Response Surface Method (RSM) Methodology for Optimizing Jettability Operating Conditions

2018 ◽  
Vol 2 (4) ◽  
pp. 51 ◽  
Author(s):  
Nuno Couto ◽  
Valter Silva ◽  
João Cardoso ◽  
Leo M. González-Gutiérrez ◽  
Antonio Souto-Iglesias
Keyword(s):  
Response Surface ◽  
Response Surface Method ◽  
Desirability Function ◽  
Operating Conditions ◽  
Function Concept ◽  
Finite Volume Model ◽  
Volume Model ◽  
On Demand ◽  
Drop On Demand ◽  
Surface Method

A volume-of-fluid (VOF) finite volume model under the ANSYS® Fluent framework was coupled with the response surface method (RSM) to find the best operating conditions within a jettability window for two selected responses in a drop-on-demand inkjet printing process. Twenty-five runs were generated using a face centred design and numerical simulations were carried out using viscosity, surface tension, nozzle diameter, and inlet velocity as input factors. A mesh study was first conducted to establish the necessary number of cells to best combine accuracy and expended time. Selected runs were discussed, identifying the underpinning mechanisms behind the droplet generation at different time periods. Each one of the responses was evaluated under different input factors and their effects were identified. Finally, the desirability function concept was advantageously used to proceed with a multiple optimization where all the responses were targeted under usual jettability/printability conditions.

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