Computational fluid dynamics investigation and multi-objective optimization of an engine air-cooling system using genetic algorithm

Author(s):  
B Najafi ◽  
H Najafi ◽  
M D Idalik

In this study, computational fluid dynamics (CFD) analysis is utilized in order to determine the convective heat transfer coefficient of an engine air-cooling system in different air velocity conditions. Various models with different geometric configurations are considered. Based on the CFD results, two formulas are proposed to approximate the values of convective heat transfer coefficients in zero and non-zero air velocities. Finally, two conflicting objective functions including volume of the required material for construction of the finned cylinder and heat release per unit temperature difference are considered. Multi-objective optimization using genetic algorithm is utilized, which generates a multiple set of solutions, each of which is a trade-off between two objectives. The user can select each of the optimal geometric configurations based on the project's requirements. In other words, considering the desired thermal design, designer is able to find the minimum volume of the required material for construction of the finned cylinder, which in turn leads to the least possible capital cost.

2015 ◽  
Vol 76 ◽  
pp. 449-461 ◽  
Author(s):  
Mehdi A. Ehyaei ◽  
Mojtaba Tahani ◽  
Pouria Ahmadi ◽  
Mohammad Esfandiari

2020 ◽  
Vol 197 ◽  
pp. 06003
Author(s):  
Maria Faruoli ◽  
Annarita Viggiano ◽  
Paolo Caso ◽  
Vinicio Magi

It is well known that spark ignition internal combustion engines for aeronautical applications operate within a specific temperature range to avoid structural damages, detonations and loss of efficiency of the combustion process. An accurate assessment of the cooling system performance is a crucial aspect in order to guarantee broad operating conditions of the engine. In this framework, the use of a Conjugate Heat Transfer method is a proper choice, since it allows to estimate both the heat fluxes between the engine walls and the cooling air and the temperature distribution along the outer wall surfaces of the engine, and to perform parametric analyses by varying the engine operating conditions. In this work, the air-cooling system of a 4-cylinder spark ignition engine, designed by CMD Engine Company for aeronautical applications, is analysed in order to evaluate the amount of the air mass flow rate to guarantee the heat transfer under full load operating conditions. A preliminary validation of the model is performed by comparing the results with available experimental data. A parametric study is also performed to assess the influence of the controlling parameters on the cooling system efficiency. This study is carried out by varying the inlet air mass flow rate from 1.0 kg/s to 1.5 kg/s and the temperature of the inner wall surfaces of the engine combustion chambers from 390 K to 430 K.


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