Experimental Research on Combustion and Emission Performance for Micro Combustor of MTPV System with Stratified Porous Media

2012 ◽  
Vol 608-609 ◽  
pp. 934-940
Author(s):  
Jian Wu ◽  
Bo Li ◽  
Bin Xu ◽  
Jia Xuan Miao
Keyword(s):  
Porous Media ◽  
Temperature Distribution ◽  
Band Gap ◽  
Experimental Research ◽  
Wall Temperature ◽  
Combustion Efficiency ◽  
Critical Component ◽  
Uniform Temperature ◽  
The Past ◽  
Micro Combustor

As the critical component of the system, micro-combustor requires a high and uniform temperature distribution along the wall to meet demands for the band gap of the PV cells. The past experiments have proved that the peak wall temperature of the combustor with porous media increases obviously. This paper will have a research on stratified porous media to enhance the combustion efficiency of the combustor and reduce the emissions.

scholarly journals Numerical simulation of porous media combustion for high temperature heat exchanger

2018 ◽  
Vol 192 ◽  
pp. 02016
Author(s):  
Panu Iamsakulpanich ◽  
Kittipass Wasinarom ◽  
Thanathon Sesuk ◽  
Jarruwat Charoensuk ◽  
Katsunori Hanamura ◽  
...  
Keyword(s):  
Porous Media ◽  
Temperature Distribution ◽  
Uniform Temperature ◽  
Reaction Equation ◽  
Temperature Heat ◽  
1D Model ◽  
Burner Design ◽  
Porous Media Combustion ◽  
Porous Media Burner

The purpose of this work is developing the numerical 1D model of porous media combustion for investigating porous media burner systems. The software is used to solve energy, mass transfer and chemical reaction equation of the combustion. The operating condition and property parameters, which mainly affect the functions and quality of the industrial burner design, such as the inlet velocity of the reactants, the equivalence ratio, the extinction coefficient and the thermal conductivity of porous media, will be investigated and validated with experimental data. For developing the procedure of experiment, three diameter sizes of porous media materials (5 mm, 10 mm, and 15 mm.) were used. As a result, the developed model will be used as a tool to explore temperature distribution of heat exchange to improve thermal performance and overall efficiency system. Moreover, this knowledge can be applied to design porous media burner systems for uniform temperature distribution operation.

scholarly journals Effect of Channel Diameter on the Combustion and Thermal Behavior of a Hydrogen/Air Premixed Flame in a Swirl Micro-Combustor

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3821 ◽  
Author(s):  
Xiao Yang ◽  
Zhihong He ◽  
Lei Zhao ◽  
Shikui Dong ◽  
Heping Tan
Keyword(s):  
Thermal Conductivity ◽  
Thermal Behavior ◽  
Thermal Performance ◽  
Wall Temperature ◽  
Outer Wall ◽  
Combustion Efficiency ◽  
Premixed Flame ◽  
Channel Diameter ◽  
Recirculation Zones ◽  
Micro Combustor

Improving the flame stability and thermal behavior of the micro-combustor (MC) are major challenges in microscale combustion. In this paper, the micro combustions of an H2/air premixed flame in a swirl MC with various channel diameters (Din = 2, 3, 4 mm) were analyzed based on an established three-dimensional numerical model. The effects of hydrogen mass flow rate, thermal conductivity of walls, and the preferential transport of species were investigated. The results indicated that the flame type was characterized by the presence of two recirculation zones. The flame was anchored by the recirculation zones, and the anchoring location of the flame root was the starting position of the recirculation zones. The recirculation zones had a larger distribution of local equivalence ratio, especially in the proximity of the flame root, indicating the formation of a radical pool. The combustion efficiency increased with an increasing Din due to the longer residence time of the reactants. Furthermore, the MC with Din = 2 mm obtained the highest outer wall temperature distribution. However, the MC with Din = 4 mm had a better uniformity of outer wall temperature and large emitter efficiency due to the larger radiation surface. An increase in thermal conductivity boosts the thermal performance of combustion efficiency, emitter efficiency, and wall temperature uniformity. But there is a critical point of thermal conductivity that can increase the thermal performance. The above results can offer us significant guidance for designing MC with high thermal performance.

Understanding the Effect of Wall Conditions and Engine Geometry on Thermal Stratification and HCCI Combustion

2014 ◽  
Author(s):  
Benjamin Lawler ◽  
Satyum Joshi ◽  
Joshua Lacey ◽  
Orgun Guralp ◽  
Paul Najt ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Heat Release ◽  
Wall Temperature ◽  
Compression Ratio ◽  
Thermal Stratification ◽  
Ceramic Coatings ◽  
Combustion Efficiency ◽  
Noticeable Effect ◽  
Hcci Engine ◽  
Hcci Combustion

Thermal stratification of the unburned charge in the cylinder has a profound effect on the burn characteristics of a Homogeneous Charge Compression Ignition (HCCI) engine. Experimental data was collected in a single cylinder, gasoline-fueled, HCCI engine in order to determine the effects of combustion chamber geometry and wall conditions on thermal stratification and HCCI combustion. The study includes a wall temperature sweep and variations of piston top surface material, piston top geometry, and compression ratio. The data is processed with a traditional heat release routine, as well as a post-processing tool termed the Thermal Stratification Analysis, which calculates an unburned temperature distribution from heat release. For all of the sweeps, the 50% burned point was kept constant by varying the intake temperature. Keeping the combustion phasing constant ensures the separation of the effects of combustion phasing from the effects of wall conditions alone on HCCI and thermal stratification. The results for the wall temperature sweep show no changes to the burn characteristics once the combustion phasing has been matched with intake temperature. This result suggests that the effects of wall temperature on HCCI are mostly during the gas-exchange portion of the cycle. The ceramic coatings were able to very slightly decrease the thermal width, increase the burn rate, increase the combustion efficiency, and decrease the cumulative heat loss. The combustion efficiency increased with the lower surface area to volume ratio piston and the lower compression ratio. Lastly, the compression ratio comparison showed a noticeable effect on the temperature distribution due to the effect of pressure on ignition delay, and the variation of TDC temperature required to match combustion phasing.

scholarly journals Influence of Porous Media Aperture Arrangement on CH4/Air Combustion Characteristics in Micro Combustor

Processes ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1747
Author(s):  
Fei Wang ◽  
Xueming Li ◽  
Shuai Feng ◽  
Yunfei Yan
Keyword(s):  
Porous Media ◽  
Temperature Distribution ◽  
High Efficiency ◽  
Outer Wall ◽  
Combustion Characteristics ◽  
Combustion Stability ◽  
Mixed Gas ◽  
Radial Temperature ◽  
Combustion Performance ◽  
Micro Combustor

Micro-electro-mechanical systems (MEMS) occupy an important position in the national economy and military fields, and have attracted great attention from a large number of scholars. As an important part of the micro-electromechanical system, the micro-combustor has serious heat loss due to its small size, unstable combustion and low combustion efficiency. Aiming at enhancing the heat transfer of the micro-combustor, improving the combustion stability and high-efficiency combustion, this paper embedded porous media in the combustor, and the effects of different parameters on the combustion characteristics were numerically studied. The research results showed that the layout of porous media should be reasonable, and the small and large pore porous media embedded in the inner and outer layers, respectively, can bring better combustion performance. Meanwhile, A: 10–30 has a high and uniform temperature distribution, and its methane conversion rate reached 97.4%. However, the diameter ratio of the inner layer to the outer layer (d/D) of the porous medium should be maintained at 0.4–0.6, which brings a longer gas residence time, and further enables the pre-mixed gas to preheat and burn completely. At a d/D of 0.5, the combustor has the highest outer wall temperature and CH4 conversion efficiency. Besides, compared with the pore size increasing rate of Δn = 10 PPI and Δn = 10 PPI, the radial temperature distribution of the Δn = 10 PPI combustor is more uniform, meanwhile avoids the occurrence of local high temperature. Under the condition of Δn = 10 PPI, A: 20–30 layout maintains excellent thermal and combustion performance. In addition, the lean flammable limits of MC-U20, MC-10/30-0.8, and MC-20/30-0.5 were compared, at an inlet velocity of 0.5 m/s, the corresponding lean flammable limits are 0.5, 0.4, and 0.3, respectively, among them MC-20/30-0.5 has a wider flammable limit range, showing excellent combustion stability. This research has guiding significance for the combustion stability of the micro combustor.

scholarly journals Numerical Study on the Characteristics of Methane Hedging Combustion in a Heat Cycle Porous Media Burner

Processes ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1733
Author(s):  
Fei Wang ◽  
Xueming Li ◽  
Shuai Feng ◽  
Yunfei Yan
Keyword(s):  
Porous Media ◽  
Temperature Distribution ◽  
Energy Density ◽  
Wall Temperature ◽  
High Energy ◽  
High Energy Density ◽  
Small Scale ◽  
Cycle Structure ◽  
Heat Cycle ◽  
Micro Scale

With the rapid development of portable devices and micro-small sensors, the demand for small-scale power supplies and high-energy-density energy supply systems is increasing. Comparing with the current popular lithium batteries, micro-scale burners based on micro-thermal photoelectric systems have features of high power density and high energy density, the micro-scale burner is the most critical part of the micro-thermal photovoltaic system. In this paper, the combustor was designed as a heat cycle structure and filled with porous media to improve the combustion characteristics of the micro combustor. In addition, the influence of the porous media distribution on the burner center temperature and wall temperature distribution were studied through numerical simulation. Furthermore, the temperature distribution of the combustor was studied by changing the porous media parameters and the wall parameters. The research results show that the heat cycle structure can reduce heat loss and improve combustion efficiency. When the combustion chamber is filled with porous media, it makes the radial center temperature rise by about 50 K and the temperature distribution more uniform. When filling the heat cycle channel with porous media the wall temperature can be increased. Finally, the study also found that as methane is combusted in the combustor, the temperature of the outer wall gradually increases as the intake air velocity increases. The results of this study provide a theoretical and practical basis for the further design of high-efficiency combustion micro-scale burners in the future.

Modular Combustor-Radiator for Micro-TPV System Application

2010 ◽  
Vol 74 ◽  
pp. 93-98 ◽  
Author(s):  
Siaw Kiang Chou ◽  
W.M. Yang ◽  
Jun Li
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
Energy Density ◽  
Wall Temperature ◽  
System Application ◽  
Radiation Energy ◽  
Radiation Energy Density ◽  
Cylindrical Structure ◽  
Micro Combustor ◽  
First Time

The micro combustor is a key component of a micro thermophotovoltaic (TPV) system. In order to maximize the power output, a high wall temperature and uniform distribution along the combustor wall are desirable. Compared to the cylindrical structure, a modular TPV system has been developed with the advantages of easier fabrication and assembly. Three kinds of micro combustors with widths of 1.0 mm, 1.5 mm and 2.0 mm have been experimentally studied. The results indicate that the wall temperature decreases with the increase of width due to the weakened heat transfer between the wall and the hot gases. Other parameters affecting the performance of the micro combustor have also been studied. For the first time, a SiC porous foam was inserted in the micro combustor to enhance both the preheating of the inlet mixture and the heat transfer between the hot gases and the wall, thereby increasing the wall temperature. An increase of 80-90 K has been obtained along the wall of the micro planar combustor with SiC as porous media. This enhanced performance translates to an increase of 33% in radiation energy density.

Experimental Research on Premixed Porous Media Combustion in Multiple Ejection/Tangential Burner

2014 ◽  
Vol 709 ◽  
pp. 83-86
Author(s):  
Jiang Rong Xu ◽  
Xiang Xiang Chen ◽  
Guan Qing Wang
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Temperature Distribution ◽  
Experimental Research ◽  
Premixed Combustion ◽  
Experimental Results ◽  
Ignition Characteristic ◽  
Porous Media Combustion

In this paper, the experimental research of porous media combustion was carried on premixed combustion of multiple ejection/tangential burner, the ignition characteristic, the resistance characteristics and the temperature distribution in the burner were obtained, and the experimental results were analyzed in detailed, which can provide references for the improvements of novel porous medium burner.

scholarly journals Design and working performance study of a novel micro parallel plate combustor with two nozzles for micro thermophotovotaic system

2015 ◽  
Vol 19 (6) ◽  
pp. 2185-2194
Author(s):  
J.F. Pan ◽  
Z.Y. Hou ◽  
Y.X. Liu ◽  
A.K. Tang ◽  
J. Zhou ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Parallel Plate ◽  
Combustion Process ◽  
Three Dimensional ◽  
Volumetric Flow Rate ◽  
Combustion Efficiency ◽  
Performance Study ◽  
Power Generators ◽  
Inlet Angle ◽  
Micro Combustor

Micro-combustors are a key component in combustion-driven micro power generators, and their performance is significantly affected by their structure. For the application of micro-thermophotovoltaic (MTPV) system, a high and uniform temperature distribution along the walls of the micro combustor is desired. In this paper, a three-dimensional numerical simulation has been conducted on a new-designed parallel plate micro combustor with two nozzles. The flow field and the combustion process in the micro combustor, and the temperature distribution on the wall as well as the combustion efficiency were obtained. The effects of various parameters such as the inlet angle and the fuel volumetric flow rate on the performance of the micro combustor were studied. It was observed that a swirl formed in the center of the combustor and the radius of the swirl increased with the increase of the inlet rate, and the best working condition was achieved at the inlet angle ?=20?. The results indicated that the two-nozzle combustion chamber had a higher and more uniform mean temperature than the conventional combustor under the same condition.

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