What is a Chemical Reaction?
A chemical reaction is a process in which one or more substances, the reactants, are converted to one or more different substances, the products. Substances are either chemical elements or compounds. A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products. Chemical reactions are integral to technology, culture, and life. Burning fuels, smelting iron, making glass and pottery are examples of activities incorporating chemical reactions that have been known and used for thousands of years. Chemical reactions abound in the geology of Earth, the atmosphere, and oceans, and a vast array of complicated processes occur in all living systems. Two of the most important chemical reactions which we can simulate using CFD applications are combustion and fuel cells.
We use the Species transport model and energy equation to define the combustion process. We calculate the continuity and momentum equations for all species in this model. The reaction usually is between air and fuel. Since we inject the composition of fuel and air into a volume, we use the Volumetric reaction option. Eddy-Dissipation should be used since the criterion of the combustion reaction is assumed to be based on the rate of mixing between fuel and air. Also, the Diffusion Energy Source option is used since the reaction contains energy sources. Also, it is possible to produce pollutants during a combustion process. In some reactions, the created nitrogen oxides, including NO and NO2, are called NOx as reaction pollutants. One of the leading causes of the growth rate of these nitrogen oxides is the excessive rise in temperature inside the combustion chamber.
A fuel cell is a device that generates electricity through a chemical reaction. Fuel cells consist of two electric poles, or electrodes called the cathode and the anode. Chemical reactions take place inside these electrodes and generate electricity. In addition, each fuel cell also has an electrolyte and a catalyst, so that the task of the electrolyte is to move charged particles between the electrodes, and the mission of catalysts is to increase the rate of reaction at the electrodes. One of the essential features of these fuel cells is the production of electricity with the lowest pollution levels. Hydrogen is the primary fuel input to the cell, but oxygen is also needed to form the reaction. Finally, most oxygen and hydrogen entering the cell are discharged as a safe product (water). Since each fuel cell generates only a minimal amount of direct current, it is usually attempted to use a large number of cells in large batches called the stack. The advantage of fuel cells compared to other sources and methods of electricity generation is that the fuel cell generates electricity by chemical reaction without a combustion reaction; therefore, these fuel cells are more efficient and work less costly. The disadvantage of these cells is that they are challenging to build despite their relatively simple operation.
You can see the projects ‘Two Stream Combustion’ and ‘Fuel Cell (PEMFC)’ links below, which are carried out by the MR-CFD team:
MR-CFD, an Expert in the Field of CFD Simulations
With several years of experience in simulating various problems in various CFD fields using ANSYS Fluent software, the MR-CFD team is ready to offer extensive modeling, meshing, and simulation services based on the need of our customers. Our services are not limited to the mentioned subject, and the MR-CFD team is ready to undertake different and challenging projects. You can consult with our experts freely and without charge and order your project by sending the problem details to us using the following address.
By outsourcing your project to the MR-CFD as a CFD simulation freelancer, you will not only receive the related project’s files (Geometry, Mesh, …), but also you will be provided with an extensive tutorial video demonstrating how you can create the geometry, mesh, and define the needed settings(pre-processing, processing and post-processing) in the ANSYS Fluent software all by yourself. Additionally, post-technical support is available to clarify issues and ambiguities.