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Effects of electric field on micro-scale flame properties of biobutanol fuel

View Article: PubMed Central - PubMed

ABSTRACT

With the increasing need of smaller power sources for satellites, energy systems and engine equipment, microcombustion pose a potential as alternative power source to conventional batteries. As the substitute fuel source for gasoline, biobutanol shows more promising characteristics than ethanol. In this study, the diffusion microflame of liquid biobutanol under electric field have been examined through in-lab experiment and numerical simulation. It is found that traditional gas jet diffusion flame theory shows significant inconsistency with the experimental results of micro scale flame in electric field. The results suggest that with the increase of electric field intensity, the quenching flow rate decrease first and increase after it reach its minimum, while the flame height and highest flame temperature increase first and drop after its peak value. In addition, it was also observed that the flame height and highest temperature for smaller tube can reach its maximum faster. Therefore, the interaction between microscale effect and electric field plays a significant role on understanding the microcombustion of liquid fuel. Therefore, FLUENT simulation was adopted to understand and measure the impacts of microflame characteristic parameters. The final numerical results are consistent with the experimental data and show a high reliability.

No MeSH data available.


Grid system for combustion.
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f2: Grid system for combustion.

Mentions: A computational fluid dynamic (CFD) software, Fluent, is used for the numerical analysis. User-defined Scalar (UDS) package in Fluent 6.3 is adopted to solve electric fluid dynamics problems. Because the micro-scale combustion have special properties, such as a very short residence time, increased surface area volume ratio, significant viscous effect, and large quantity of heat loss and so on, it is very important to select 3 D model for the accurate predictability of combustion process. The suited 3 D model as shown in Fig. 2 includes burning zone outside tube, tube wall and flowing zone inside tube. Combining the characteristic of laminar flow diffusion combustion, a 3D cylinder combustion model with height of 40 mm and diameter of 10 mm is created. The height of tube 1 and tube 2 are set as 8 mm in the experiment. The models are created and meshed by GAMBIT, a pre-processing software package in Fluent. After a test on the mesh number effects, 208 351 and 59 950 hexahedral elements were generated for tube 1 and tube 2. Then, the model was exported to Fluent with boundary conditions and material properties set to default. The interface between the tube and fuel was treated as a coupled wall.


Effects of electric field on micro-scale flame properties of biobutanol fuel
Grid system for combustion.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5016967&req=5

f2: Grid system for combustion.
Mentions: A computational fluid dynamic (CFD) software, Fluent, is used for the numerical analysis. User-defined Scalar (UDS) package in Fluent 6.3 is adopted to solve electric fluid dynamics problems. Because the micro-scale combustion have special properties, such as a very short residence time, increased surface area volume ratio, significant viscous effect, and large quantity of heat loss and so on, it is very important to select 3 D model for the accurate predictability of combustion process. The suited 3 D model as shown in Fig. 2 includes burning zone outside tube, tube wall and flowing zone inside tube. Combining the characteristic of laminar flow diffusion combustion, a 3D cylinder combustion model with height of 40 mm and diameter of 10 mm is created. The height of tube 1 and tube 2 are set as 8 mm in the experiment. The models are created and meshed by GAMBIT, a pre-processing software package in Fluent. After a test on the mesh number effects, 208 351 and 59 950 hexahedral elements were generated for tube 1 and tube 2. Then, the model was exported to Fluent with boundary conditions and material properties set to default. The interface between the tube and fuel was treated as a coupled wall.

View Article: PubMed Central - PubMed

ABSTRACT

With the increasing need of smaller power sources for satellites, energy systems and engine equipment, microcombustion pose a potential as alternative power source to conventional batteries. As the substitute fuel source for gasoline, biobutanol shows more promising characteristics than ethanol. In this study, the diffusion microflame of liquid biobutanol under electric field have been examined through in-lab experiment and numerical simulation. It is found that traditional gas jet diffusion flame theory shows significant inconsistency with the experimental results of micro scale flame in electric field. The results suggest that with the increase of electric field intensity, the quenching flow rate decrease first and increase after it reach its minimum, while the flame height and highest flame temperature increase first and drop after its peak value. In addition, it was also observed that the flame height and highest temperature for smaller tube can reach its maximum faster. Therefore, the interaction between microscale effect and electric field plays a significant role on understanding the microcombustion of liquid fuel. Therefore, FLUENT simulation was adopted to understand and measure the impacts of microflame characteristic parameters. The final numerical results are consistent with the experimental data and show a high reliability.

No MeSH data available.