Numerical solution on the effects of bluff body with slit in micro-channel combustor

Small-scale electronic devices required long hours operation and fast charging time. Potential technology to support requirement of small-scale electronic device is micro scale combustor. Production of heat in micro level from progression of exothermic chemical reaction between reactants is known as...

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Main Author:	Wan Shuib, Wan Mohd Amin
Format:	Thesis
Language:	English English
Published:	2018
Subjects:	TJ Mechanical engineering and machinery
Online Access:	http://ir.upnm.edu.my/id/eprint/253/1/NUMERICAL%20SOLUTION%20ON%20%2825p%29.pdf http://ir.upnm.edu.my/id/eprint/253/2/NUMERICAL%20SOLUTION%20ON%20%28Full%29.pdf
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spelling	my-upnm-ir.2532023-09-05T03:03:35Z Numerical solution on the effects of bluff body with slit in micro-channel combustor 2018-09-26 Wan Shuib, Wan Mohd Amin TJ Mechanical engineering and machinery Small-scale electronic devices required long hours operation and fast charging time. Potential technology to support requirement of small-scale electronic device is micro scale combustor. Production of heat in micro level from progression of exothermic chemical reaction between reactants is known as micro combustion and may be utilized to generate electricity for small-scale electronic devices. Unfortunately, micro scale combustion is prone to combustion instability. This research is to study micro scale combustion with slit. Therefore, objective of this study is to investigate the combustion characteristics, mechanism that stabilize the flame and combustor performance of the 2-D microchannel combustor with bluff body having various slit percentages gap using ANSYS Fluent 15.7. Effects of the bluff body with slit in the micro-channel combustor have been studied numerically. Two-dimensional computational domain with the height and length of the channel H = 1 mm and L = 16 mm is used respectively. The height of the bluff body is 0.5 mm and located at 2 mm from the inlet. The slit gap percentage varied in this study is 0% to 70%. The percentage of the slit size is the ratio between slit gap height and the bluff body height. The one-step reaction mechanism of CH4/air mixture is utilized. Equivalence ratios of 0.8 to 1.0 with inlet velocities 1.0 m/s to 5.0 m/s were used. The results show that the combustion characteristic such as stable flame, wavy flame, blow-off and flame split into two parts is significantly influenced by the slit gap percentage. Flame is moving downstream and blow-off at the slit percentage of 10% to 25%. At the slit percentage of 30%, the flame zone moves towards the upstream result in stable flame. From the observation is suggested due to the secondary vortex exist behind the bluff body as slit gap increases and pull or push the flame to the upstream or downstream. The reaction zone is split into two parts at 60% and 70% slit gap percentage. It is due to the incoming fresh mixture of CH4/air mixture flows through the slit and cut the flame zone. It is also found that by increasing inlet velocity beyond 2.0 m/s, the flame become unstable and lead to blow-off as increase in equivalence ratio up to 1.0. Lastly, the highest emitter efficiency is found for the case of 40% slit which is 25 W/m. 2018-09 Thesis http://ir.upnm.edu.my/id/eprint/253/ http://ir.upnm.edu.my/id/eprint/253/1/NUMERICAL%20SOLUTION%20ON%20%2825p%29.pdf text en public http://ir.upnm.edu.my/id/eprint/253/2/NUMERICAL%20SOLUTION%20ON%20%28Full%29.pdf text en validuser mphil masters Universiti Pertahanan Nasional Malaysia Centre For Graduate Studies
institution	Universiti Pertahanan Nasional Malaysia
collection	UPNM Institutional Repository
language	English English
topic	TJ Mechanical engineering and machinery
spellingShingle	TJ Mechanical engineering and machinery Wan Shuib, Wan Mohd Amin Numerical solution on the effects of bluff body with slit in micro-channel combustor
description	Small-scale electronic devices required long hours operation and fast charging time. Potential technology to support requirement of small-scale electronic device is micro scale combustor. Production of heat in micro level from progression of exothermic chemical reaction between reactants is known as micro combustion and may be utilized to generate electricity for small-scale electronic devices. Unfortunately, micro scale combustion is prone to combustion instability. This research is to study micro scale combustion with slit. Therefore, objective of this study is to investigate the combustion characteristics, mechanism that stabilize the flame and combustor performance of the 2-D microchannel combustor with bluff body having various slit percentages gap using ANSYS Fluent 15.7. Effects of the bluff body with slit in the micro-channel combustor have been studied numerically. Two-dimensional computational domain with the height and length of the channel H = 1 mm and L = 16 mm is used respectively. The height of the bluff body is 0.5 mm and located at 2 mm from the inlet. The slit gap percentage varied in this study is 0% to 70%. The percentage of the slit size is the ratio between slit gap height and the bluff body height. The one-step reaction mechanism of CH4/air mixture is utilized. Equivalence ratios of 0.8 to 1.0 with inlet velocities 1.0 m/s to 5.0 m/s were used. The results show that the combustion characteristic such as stable flame, wavy flame, blow-off and flame split into two parts is significantly influenced by the slit gap percentage. Flame is moving downstream and blow-off at the slit percentage of 10% to 25%. At the slit percentage of 30%, the flame zone moves towards the upstream result in stable flame. From the observation is suggested due to the secondary vortex exist behind the bluff body as slit gap increases and pull or push the flame to the upstream or downstream. The reaction zone is split into two parts at 60% and 70% slit gap percentage. It is due to the incoming fresh mixture of CH4/air mixture flows through the slit and cut the flame zone. It is also found that by increasing inlet velocity beyond 2.0 m/s, the flame become unstable and lead to blow-off as increase in equivalence ratio up to 1.0. Lastly, the highest emitter efficiency is found for the case of 40% slit which is 25 W/m.
format	Thesis
qualification_name	Master of Philosophy (MPhil)
qualification_level	Master's degree
author	Wan Shuib, Wan Mohd Amin
author_facet	Wan Shuib, Wan Mohd Amin
author_sort	Wan Shuib, Wan Mohd Amin
title	Numerical solution on the effects of bluff body with slit in micro-channel combustor
title_short	Numerical solution on the effects of bluff body with slit in micro-channel combustor
title_full	Numerical solution on the effects of bluff body with slit in micro-channel combustor
title_fullStr	Numerical solution on the effects of bluff body with slit in micro-channel combustor
title_full_unstemmed	Numerical solution on the effects of bluff body with slit in micro-channel combustor
title_sort	numerical solution on the effects of bluff body with slit in micro-channel combustor
granting_institution	Universiti Pertahanan Nasional Malaysia
granting_department	Centre For Graduate Studies
publishDate	2018
url	http://ir.upnm.edu.my/id/eprint/253/1/NUMERICAL%20SOLUTION%20ON%20%2825p%29.pdf http://ir.upnm.edu.my/id/eprint/253/2/NUMERICAL%20SOLUTION%20ON%20%28Full%29.pdf
_version_	1813223594136698880

Numerical solution on the effects of bluff body with slit in micro-channel combustor

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