1

Simulation of multiple char reactions for coal combustion

Simulation of multiple char reactions for coal combustion

Introduction

Thepurposeofthistutorialistoprovideguidelinesandrecommendationstosetupandsolve multiple char reactions for coal combustion or gasification using finite-rate/eddy-dissipation model. This tutorial demonstrates how to do the following:

  • Use discrete phase model to set up and solve multiple char reactions for coal combustion.
  • Activate and set up the finite-rate/eddy-dissipation model for the reactions occurring during combustion.
  • Solve the case using appropriate solver settings.
  • Postprocess the resulting data.
  • Include the radiation model and study its effect on reaction temperature.

Prerequisites

This tutorial is written with the assumption that you have completed Tutorial 1 from ANSYS FLUENT 14.5 Tutorial Guide, and that you are familiar with the ANSYS FLUENT navigation pane and menu structure. Some steps in the setup and solution procedure will not be shown explicitly. In this tutorial, you will use turbulence and combustion models, so you should have some experience with them. This tutorial will focus on the application of these models in coal combustion and will not cover the mechanics of using these models

Problem Description

The coal combustion system considered in this tutorial is a simple 10 m × 1 m two-dimensional duct as shown in Figure 1. Only half of the domain width is modeled because of symmetry. The inlet of the 2D duct is split into two streams. A high-speed stream near the center of the duct enters at 50 m/s and spans 0.125 m. The other stream enters at 15 m/s and spans 0.375 m. Both streams are air at 1500 K. Coal particles enter the furnace near the center of the high-speed stream with a mass flow rate of 0.1 kg/s (total flow rate in the furnace is 0.2 kg/s). The duct wall has a constant temperature of 1200 K. The Reynolds number, based on the inlet dimension and the average inlet velocity is approximately 100,000. Thus, the flow is turbulent.

Result

In this tutorial, an injection group is introduced at the inlet. The coal-mv particles travel a distance before they start releasing volatiles. The reaction starts at this point and the temperature increases. The radiation model lowers the peak temperature by taking the heat away from the reaction zone. In finite-rate/eddy-dissipation coal combustion, coal particles release volatiles that react with oxygen and produce combustion products. The stoichiometric coefficients can be calculated once chemical composition of coal volatiles is known. For information on determining coal volatile composition, see tutorial, Using the Non-Premixed Combustion Model in the ANSYS FLUENT 14.5 Tutorial Guide.

Summary

Application of multiple char reactions and finite-rate/eddy-dissipation model in a coal combustion case has been demonstrated.

Mr CFD Company services

Due to the wide range of mechanical science and the different fields of work as well as the abundance of projects, this company offers to view all the products presented in this section. In the absence of any desired project or project close to your request, you can search our portfolios in order to find your eligible project, after all, if you didn’t find any ideal project you can order your project from the services pages on the header of this website. Your order will be reviewed by our experts in the shortest possible time, and if we need more information about the proposed project, we will be in touch with you. After completing the required information to examine the proposed project, and confirming your request, the time, conditions and costs will be sent to you during the contract. This process will take place as soon as possible. If you have any question, you can contact to our online support section (the fixed blue tab below the page). If it is offline, don’t worry, you can post your message, and it will be answered as soon as possible.

Leave a Reply

Your email address will not be published. Required fields are marked *

Call On WhatsApp
Search