مهندسی مکانیک مدرس

مهندسی مکانیک مدرس

حل عددی جریان سیال سمت کاتد پیل سوختی غشاء پلیمری دارای توزیع کننده فوم با تخلخل غیریکنواخت

نوع مقاله : پژوهشی اصیل

نویسندگان
1 دانشگاه علم و صنعت ایران
2 دانشگاه صنعتی امیرکبیر
3 دانشگاه جهرم
چکیده
اخیرا در بسیاری از کاربردهای پیل سوختی، به­منظور افزایش بازدهی و یکنواخت­تر کردن توزیع واکنش­دهنده­ها در سطح فعال، از فوم به عنوان توزیع کننده جریان استفاده می شود. اما این روش علیرغم ایجاد بهبود نسبی در بازدهی و عملکرد پیل سوختی، توزیع واکنش­دهنده­ها را به یکنواختی مطلوب نمی­رساند. از این رو در این مطالعه، از فوم فلزی با تخلخل غیر یکنواخت جهت توزیع همگن­تر جریان هوا در سمت کاتد پیل سوختی غشا پلیمری استفاده شده­ است. در ابتدا فوم به صورت یکنواخت و با تخلخل یکسان فرض شده است. پس از حل عددی جریان در فوم همگن (نوع اول)، دو نوع فوم با ضریب تخلخل متغیر طراحی شده­ است به­گونه­ای که با تقسیم فوم به شکل شطرنجی، ضرایب تخلخل در گوشه­های مقعر که کسر مولی اکسیژن در آن­ها پایین است (نواحی مرده)، حائز مقدار بالاتری هستند تا حرکت جریان به این گوشه­ها تسهیل و در نتیجه توزیع جریان نیز یکنواخت­تر شود. نتایج شبیه سازی حاکی از آن بود که به ازای چگالی جریان ثابت، توزیع کسر مولی اکسیژن در هر دو نوع فوم با ضریب تخلخل متغیر، یکنواخت­تر شده و متوسط کسر مولی اکسیژن نیز در فوم نوع دوم 45/9% و در فوم نوع سوم 02/32% نسبت به فوم یکنواخت افزایش داشته، همچنین گرادیان فشار در فوم با تخلخل متغیر نوع دوم، 75/80% نسبت به فوم یکنواخت افزایش یافته، در حالی که به ازای فوم نوع سوم، تغییر چندانی نداشته است.
کلیدواژه‌ها

موضوعات


عنوان مقاله English

Numerical Investigation of Fluid Flow in the Cathode Side of Polymer Membrane Fuel Cell with Foam-Based Distributor with Non-Uniform Porosity

نویسندگان English

Mohammad Erfan Maleki 1
Mohammad Javad Keikhaei 2
Mahbod Moein Jahromi 3
Mohammad Jafar Kermani 2
1 Iran University of Science and Technology
2 Amirkabir University of Technology
3 University of Jahrom
چکیده English

Recently, in many fuel cell applications, foam is being used as a flow distributor to increase efficiency and achieve a more uniform distribution of reactants on the active surface. However, despite the improvement in the efficiency and performance of the fuel cell, this method does not fully achieve the desired uniformity in reactant distribution. Therefore, in this study, non-uniform porosity metal foam has been utilized to improve the homogeneous flow distribution on the cathode side of the PEM fuel cell. At first, the foam is assumed to be uniform with the same porosity. After the numerical solution of the flow in homogeneous foam (first type), Two types of foam with variable porosity coefficient have been designed. These foams are divided into checkerboard shape, where the porosity coefficients in the concave corners (dead areas) with low molar fraction of oxygen are higher. This facilitates easier movement of the flow towards these corners, resulting in a more uniform flow distribution. the simulation results indicate that, for a constant current density, the distribution of the mole fraction of oxygen in both types of foam with a variable porosity coefficient has become more uniform. Additionally, the average molar fraction of oxygen has increased by 9.45% in the second type of foam and by 32.02% in the third type of foam compared to the uniform foam, which indicates an increase in generated power. Also, compared to the uniform foam, the pressure gradient in the foam with variable porosity of the second type increased by 75.80%, while it remained relatively unchanged for the third type foam.

کلیدواژه‌ها English

fuel cell
Metal Foam-Based Distributor
Variable Porosity Foam
Uniform Flow Distribution
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