The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Aikun Tang - One of the best experts on this subject based on the ideXlab platform.
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hydrogen oxygen premixed combustion characteristics in micro Porous Media combustor
Applied Energy, 2015Co-Authors: D Wu, H F Zhang, Aikun TangAbstract:The micro-combustor is a major component of the micro thermophotovoltaic (TPV) system. In order to improve the stability of combustion and efficiency of the micro-TPV conversion device, Porous Media combustor was designed. Porous Media combustion can increase flame stability and gain higher conversion efficiency compared with the free flame combustor. In this work, the influence of several major parameters on micro combustion, namely material of Porous Media, hydrogen to oxygen equivalence ratio, porosity of Porous Media and mixture flow rate were investigated using the numerical simulation method. Results indicate that, even though at three different equivalence ratio conditions, SiC is still one of the most suitable Porous Media materials. Besides, high flow velocity and big porosity both induce high temperature gradient and big pressure drop. The interaction between these two parameters plays an important role in external wall temperature. Analyses in this paper reveal that with the appropriate parameters: ϕ=0.8, v=6m/s, porosity is 0.5 and Porous Media material is SiC, micro combustor with Porous Media structure could greatly increase combustion efficiency. Present research will facilitate the optimization and improvement of micro-TPV conversion device.
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hydrogen oxygen premixed combustion characteristics in micro Porous Media combustor
Energy Procedia, 2014Co-Authors: D Wu, H F Zhang, Aikun TangAbstract:Abstract The micro-combustor is a major component of the micro thermophotovoltaic system. In order to improve the stability and performance efficiency of micro-TPV conversion device, Porous Media combustor was designed. Porous Media combustion can increase flame stability and gain higher conversion efficiency compared with free flame combustor. In this work, the effects of several major parameters on micro combustion, namely material of Porous Media, hydrogen to oxygen equivalence ratio, porosity of Porous Media and mixture flow rates were investigated using numerical simulation method. Results indicated that, even though at three different equivalence ratio conditions, SiC is still one of the most suitable Porous Media material. Besides, high flow velocity and big porosity both lead to high temperature gradient and big pressure drop. The interaction between these two parameters plays an important role in external wall temperature. Analyses reveal that with the appropriate parameters, micro combustor with Porous Media structure could greatly increase combustion efficiency. Present research will facilitate the optimization and improvement of micro-TPV conversion device.
D Wu - One of the best experts on this subject based on the ideXlab platform.
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hydrogen oxygen premixed combustion characteristics in micro Porous Media combustor
Applied Energy, 2015Co-Authors: D Wu, H F Zhang, Aikun TangAbstract:The micro-combustor is a major component of the micro thermophotovoltaic (TPV) system. In order to improve the stability of combustion and efficiency of the micro-TPV conversion device, Porous Media combustor was designed. Porous Media combustion can increase flame stability and gain higher conversion efficiency compared with the free flame combustor. In this work, the influence of several major parameters on micro combustion, namely material of Porous Media, hydrogen to oxygen equivalence ratio, porosity of Porous Media and mixture flow rate were investigated using the numerical simulation method. Results indicate that, even though at three different equivalence ratio conditions, SiC is still one of the most suitable Porous Media materials. Besides, high flow velocity and big porosity both induce high temperature gradient and big pressure drop. The interaction between these two parameters plays an important role in external wall temperature. Analyses in this paper reveal that with the appropriate parameters: ϕ=0.8, v=6m/s, porosity is 0.5 and Porous Media material is SiC, micro combustor with Porous Media structure could greatly increase combustion efficiency. Present research will facilitate the optimization and improvement of micro-TPV conversion device.
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hydrogen oxygen premixed combustion characteristics in micro Porous Media combustor
Energy Procedia, 2014Co-Authors: D Wu, H F Zhang, Aikun TangAbstract:Abstract The micro-combustor is a major component of the micro thermophotovoltaic system. In order to improve the stability and performance efficiency of micro-TPV conversion device, Porous Media combustor was designed. Porous Media combustion can increase flame stability and gain higher conversion efficiency compared with free flame combustor. In this work, the effects of several major parameters on micro combustion, namely material of Porous Media, hydrogen to oxygen equivalence ratio, porosity of Porous Media and mixture flow rates were investigated using numerical simulation method. Results indicated that, even though at three different equivalence ratio conditions, SiC is still one of the most suitable Porous Media material. Besides, high flow velocity and big porosity both lead to high temperature gradient and big pressure drop. The interaction between these two parameters plays an important role in external wall temperature. Analyses reveal that with the appropriate parameters, micro combustor with Porous Media structure could greatly increase combustion efficiency. Present research will facilitate the optimization and improvement of micro-TPV conversion device.
H F Zhang - One of the best experts on this subject based on the ideXlab platform.
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hydrogen oxygen premixed combustion characteristics in micro Porous Media combustor
Applied Energy, 2015Co-Authors: D Wu, H F Zhang, Aikun TangAbstract:The micro-combustor is a major component of the micro thermophotovoltaic (TPV) system. In order to improve the stability of combustion and efficiency of the micro-TPV conversion device, Porous Media combustor was designed. Porous Media combustion can increase flame stability and gain higher conversion efficiency compared with the free flame combustor. In this work, the influence of several major parameters on micro combustion, namely material of Porous Media, hydrogen to oxygen equivalence ratio, porosity of Porous Media and mixture flow rate were investigated using the numerical simulation method. Results indicate that, even though at three different equivalence ratio conditions, SiC is still one of the most suitable Porous Media materials. Besides, high flow velocity and big porosity both induce high temperature gradient and big pressure drop. The interaction between these two parameters plays an important role in external wall temperature. Analyses in this paper reveal that with the appropriate parameters: ϕ=0.8, v=6m/s, porosity is 0.5 and Porous Media material is SiC, micro combustor with Porous Media structure could greatly increase combustion efficiency. Present research will facilitate the optimization and improvement of micro-TPV conversion device.
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hydrogen oxygen premixed combustion characteristics in micro Porous Media combustor
Energy Procedia, 2014Co-Authors: D Wu, H F Zhang, Aikun TangAbstract:Abstract The micro-combustor is a major component of the micro thermophotovoltaic system. In order to improve the stability and performance efficiency of micro-TPV conversion device, Porous Media combustor was designed. Porous Media combustion can increase flame stability and gain higher conversion efficiency compared with free flame combustor. In this work, the effects of several major parameters on micro combustion, namely material of Porous Media, hydrogen to oxygen equivalence ratio, porosity of Porous Media and mixture flow rates were investigated using numerical simulation method. Results indicated that, even though at three different equivalence ratio conditions, SiC is still one of the most suitable Porous Media material. Besides, high flow velocity and big porosity both lead to high temperature gradient and big pressure drop. The interaction between these two parameters plays an important role in external wall temperature. Analyses reveal that with the appropriate parameters, micro combustor with Porous Media structure could greatly increase combustion efficiency. Present research will facilitate the optimization and improvement of micro-TPV conversion device.
Zhenqian Chen - One of the best experts on this subject based on the ideXlab platform.
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Pore Structure Reconstruction and Moisture Migration in Porous Media
Fractals, 2014Co-Authors: Jiayi Zheng, Xing Shi, Juan Shi, Zhenqian ChenAbstract:Three kinds of Porous Media (isotropic, perpendicular anisotropic and parallel anisotropic Porous Media) with the same porosity, different pore size distributions and fractal spectral dimensions were reconstructed by random growth method. It was aimed to theoretically study the impact of microscopic pore structure on water vapor diffusion process in Porous Media. The results show that pore size distribution can only denote the static characteristics of Porous Media but cannot effectively reflect the dynamic transport characteristics of Porous Media. Fractal spectral dimension can effectively analyze and reflect pores connectivity and moisture dynamic transport properties of Porous Media from the microscopic perspective. The pores connectivity and water vapor diffusion performance in pores of Porous Media get better with the increase of fractal spectral dimension of Porous Media. Fractal spectral dimension of parallel anisotropic Porous Media is more than that of perpendicular anisotropic Porous Media. Fractal spectral dimension of isotropic Porous Media is between parallel anisotropic Porous Media and perpendicular anisotropic Porous Media. Other macroscopic parameters such as equilibrium diffusion coefficient of water vapor, water vapor concentration variation at right boundary in equilibrium, the time when water vapor diffusion process reaches a stable state also can characterize the pores connectivity and water vapor diffusion properties of Porous Media.
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Numerical study on gas diffusion in isotropic and anisotropic fractal Porous Media (gas diffusion in fractal Porous Media)
International Journal of Heat and Mass Transfer, 2014Co-Authors: Zhenqian ChenAbstract:Abstract A binary mixture lattice Boltzmann model (LBM) is used to simulate the diffusion process in stochastic fractal Porous Media generated by the fractional Brownian motion model. The isotropic Porous Media is reconstructed from fractional Brownian rough surface using the random midpoint displacement algorithm and the binary processing. In addition, the 2D and 3D anisotropic Porous Media is generated by transforming the isotropic fractional Brownian rough surface with a structure filter. LBM is applied to simulate the diffusion processes of reconstructed isotropic and anisotropic Porous Media for various fractal dimensions. The results indicate that the increasing fractal dimension can lead to the reduction of effective diffusion coefficients at the same porosity. The degrees of anisotropy for diffusion of anisotropic Porous Media are presented with the different anisotropic strength.
Joseph W. Meadows - One of the best experts on this subject based on the ideXlab platform.
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Thermoacoustic Instability Model With Porous Media: Linear Stability Analysis and the Impact of Porous Media
Journal of Engineering for Gas Turbines and Power, 2018Co-Authors: Cody S. Dowd, Joseph W. MeadowsAbstract:Lean premixed (LPM) combustion systems are susceptible to thermoacoustic instability, which occurs when acoustic pressure oscillations are in phase with the unsteady heat release rates. Porous Media has inherent acoustic damping properties and has been shown to mitigate thermoacoustic instability; however, theoretical models for predicting thermoacoustic instability with Porous Media do not exist. In the present study, a one-dimensional (1D) model has been developed for the linear stability analysis of the longitudinal modes for a series of constant cross-sectional area ducts with Porous Media using a n-Tau flame transfer function (FTF). By studying the linear regime, the prediction of acoustic growth rates and subsequently the stability of the system is possible. A transfer matrix approach is used to solve for acoustic perturbations of pressure and velocity, stability growth rate, and frequency shift without and with Porous Media. The Galerkin approximation is used to approximate the stability growth rate and frequency shift, and it is compared to the numerical solution of the governing equations. Porous Media is modeled using the following properties: porosity, flow resistivity, effective bulk modulus, and structure factor. The properties of Porous Media are systematically varied to determine the impact on the eigenfrequencies and stability growth rates. Porous Media is shown to increase the stability domain for a range of time delays (Tau) compared to similar cases without Porous Media.
