Swirled Jet Flame Simulation and Flow Visualization Inside Rotary Kiln—CFD with PDF Approach

Hassan F Elattar,Eckehard Specht,Ali Fouda,Sameh A Nada,Ahmed Al-Zahrani,Saeed Rubaiee

doi:10.3390/pr8020159

Hassan F Elattar, Eckehard Specht + Show 4 more

Open Access

https://doi.org/10.3390/pr8020159

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Abstract

CFD (computational fluid dynamics) simulation using a commercial package (Fluent-ANSYS) on industrial rotary kilns using annulus-type burners and methane gas was carried out to examine the characteristics of the flame length and flow visualization. New influencing design and operating parameters—primary air swirl number, primary air inlet annulus diameter, and secondary air temperature—were investigated and discussed. The influence of these parameters on axial temperature distribution, axial mean mixture fractions, velocity vectors, mixture fractions, and temperature contours were investigated. The current numerical findings were compared with existing experimental results to validate the simulation approach. The results showed that the primary air swirl number had a remarkable influence on the flame length at a lower primary air inlet annulus diameter ratio of 2.3. Moreover, the flame length increased by 20% and 6% with increasing the swirl number from zero to one for primary air inlet annulus diameter ratios of 2.3 and 5, respectively, and it also increased by 19% with increasing primary air inlet annulus diameter ratio from 2.3 to 5.

Highlights

Rotary kiln is a rotated cylinder lined with refractory material and is slightly axially inclined for the production of cement or other materials
Several operating/design parameters relating to rotary kilns are still under study like primary air swirl number (Sn ), primary air inlet annulus diameter ratio, and secondary air temperature (Tsa ) on the flame length characteristic
◦ C, n pa sa o λ = 1.3, and α = 0.10 on temperature profiles and inverted mixture fraction profiles, velocity vectors, flame length, and mixture fraction contours are shown in Figures 5–9 for dp/do = 2.3 and 5

Summary

Introduction

Rotary kiln is a rotated cylinder lined with refractory material and is slightly axially inclined for the production of cement or other materials. The flame instability may lead to a large deviation in combustion gas temperatures, where the short flame can destroy the lining material and the long flame may not be capable of liberating sufficient heat to complete the chemical reaction The operating variables such as kind and flow rate of fuel have a remarkable influence on the flame characteristics [7]. Several operating/design parameters relating to rotary kilns are still under study like primary air swirl number (Sn ), primary air inlet annulus diameter ratio (dp /do ), and secondary air temperature (Tsa ) on the flame length characteristic. The current work is conducted in order to examine and discuss the influence of swirl number and annulus diameter of the primary inlet air and temperature of the secondary air on the flame length characteristic, which directly affects the thermal processes and the product’s quality throughout the rotary kiln. 2020, 8, 159length characteristic, which directly affects the thermal processes and 3the of 15 on the flame product’s quality throughout the rotary kiln

Physical

A CFD approach usingANSYS-Fluent

Model Validation

Results and Discussion

Conclusions