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Book Investigation of the Effects of Preheating on the Characteristics of Micro Combustion

Download or read book Investigation of the Effects of Preheating on the Characteristics of Micro Combustion written by Zerrin Turkeli-Ramadan and published by . This book was released on 2015 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: The requirement for efficient power sources for portable electronics and miniature mechanical devices, such as laptops, micro robots or micro aerial vehicles, has led to research on ultra micro gas turbine (UMGT). The ultra micro gas turbine is one of the most promising power sources for small scale applications due to its higher power and energy densities compared to currently used batteries. In order to realise UMGT as a viable power source, its individual components have to be developed, since downscaling introduces new problems for each component. Since the micro combustor is one of the key components of UMGT, it is an obvious area for investigation and improvement. Until now, it has been very difficult for micro combustors to achieve wide flame stability, high combustion efficiency and clean combustion with low pressure loss, due to the associated downscaling problems, such as high heat loss ratio and small residence time. In order to overcome the issues associated with smaller residence time, preheating the reactants was investigated in the present study, both experimentally and numerically. Two different domains were used in the two different methods. The effects of preheating the reactants on the flame stability and combustion characteristics were investigated experimentally on a 46 mm inner diameter quartz-walled flat flame combustor. The preheating was provided with external heaters. The flame shape and behaviour were observed with different air mass flow rates and equivalence ratios. The experimental results showed that preheating widened the flame stability limit. From the experimental results a new correlation was developed between mass flow rate, reactant temperature, air to fuel ratio and the diameter of the micro combustor. With this correlation, it is possible to determine the minimum combustor diameter required for stable flat flame combustion. Also, in order to have a stable flat flame at higher mass flow rates, the correlation enables the calculation of the required reactants temperature, and is a major contribution to the design of micro combustors. Furthermore, it was found that with the flat flame combustor, very clean, that is, almost complete combustion was achieved with both natural gas and methane as fuels. In addition, different flame holder materials were investigated for their pressure loss characteristics and usability for UMGT applications. On the other hand, the effects of preheating on the flame stability and species concentrations were investigated numerically within a 2 mm diameter micro combustor tube, over two-dimensions. The simulations were performed with both adiabatic walls and nonadiabatic walls. At high incoming flow velocities, preheating was shown to widen the flame stability limit. On the other hand, there is no advantage in preheating for low incoming flow velocities or low mass flow rates. A comparison of employing different skeletal and detailed reaction mechanisms was made. Furthermore, in the non-adiabatic case the effect of heat loss through the outer wall via convection and radiation were investigated with different heat transfer coefficients. In conclusion, preheating widens the flame stability limit and provides flame sustainability even at very small scales. The information generated in this research will help the development of UMGT as a viable alternative to conventional power sources at small scale.

Book Numerical Study on Catalytic Combustion and Extinction Characteristics of Pre mixed Methane air in Micro Flatbed Channel Under Different Parameters of Operation and Wall

Download or read book Numerical Study on Catalytic Combustion and Extinction Characteristics of Pre mixed Methane air in Micro Flatbed Channel Under Different Parameters of Operation and Wall written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Investigation of Combustion Characteristics of Low medium Heating Value Gases in an Atmospheric Pressure Combustor

Download or read book Investigation of Combustion Characteristics of Low medium Heating Value Gases in an Atmospheric Pressure Combustor written by Maher Boshra Khalil and published by . This book was released on 1984 with total page 554 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Numerical Investigation of Model Combustors for Efficiency Improvement and Miniature Applications

Download or read book Numerical Investigation of Model Combustors for Efficiency Improvement and Miniature Applications written by Miguel Alejandro Gutiérrez Contreras and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Non-premixed combustion process is an important subject in most applications of combustion. Understanding of this phenomenon is crucial in the design of reliable, efficient, economical power generation systems. Microfabrication technologies in the development of power micro electro-mechanical systems is also becoming an increasing trend nowadays and the complete understanding of microfluid dynamics and non-premixed micro-combustion phenomena will lead the success in this field. In recent years numerical simulations have become an essential tool to understand combustion process to overcome experimental problems without losing accuracy. In this study, two numerical simulations were performed on the analysis of the effect of injection on the turbulent mixing quality in a simple combustor and on the dynamics non-premixed flame street in a mesoscale channel using the commercial software Fluent®. The effect of inlet geometries were first investigated for a Lockwood-type combustor in terms of combustion and energy efficiency and an efficient design configuration is deduced. The effect of wall temperature and flow velocities on the dynamics of non-premixed flame in a scaled combustion channel was investigated in the second part of this study. The results suggest that the two main parameters affecting the development of a non-premixed flame street in a mesoscale channel are the heat transfer to and from the wall and the diffusion time of the flow. The analysis of numerical details such as grid resolution, turbulent and chemistry models is emphasized throughout the study to understand the influence of these numerical parameters on the simulated phenomenon by comparing with experimental observations.

Book A Numerical Investigation on Methane air Triple Flames

Download or read book A Numerical Investigation on Methane air Triple Flames written by Riccardo Azzoni and published by . This book was released on 1999 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Numerical Investigation of Turbulent Nonpremixed Methane air Flames

Download or read book Numerical Investigation of Turbulent Nonpremixed Methane air Flames written by Lale Demiraydin and published by . This book was released on 2002 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book A Numerical Investigation of Steady and Unsteady Methane air Partially premixed Flames

Download or read book A Numerical Investigation of Steady and Unsteady Methane air Partially premixed Flames written by Zhuang Shu and published by . This book was released on 2001 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Numerical Study of Shock induced Combustion in Methane air Mixtures

Download or read book Numerical Study of Shock induced Combustion in Methane air Mixtures written by Shaye Yungster and published by . This book was released on 1993 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Numerical Study of Shock induced Combustion in Methane air Mixtures

Download or read book Numerical Study of Shock induced Combustion in Methane air Mixtures written by Shaye Yungster and published by . This book was released on 1993 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: