Development of a powerful miniature power system with a meso-scale vortex combustor

Shimokuri, Daisuke; Taomoto, Yuuki; Matsumoto, Ryosuke

doi:10.1016/j.proci.2016.06.180

Cited by 61 publications

(19 citation statements)

References 15 publications

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“…It is interesting to note from Fig. 14 that, though many researchers have came up with various combustion based micro power generators in the past dacades [24,27,28,30,38], no system in the literature has shown to operate at high overall conversion efficiency(> 4 %) with a high power density ( > 0.08 mW/mm 3 ). There is a significant increase in both the power density and overall conversion efficiency over last two decades.…”

Section: Comparison Of Dual and Single Microcombustor Configurationsmentioning

confidence: 99%

“…They conducted a detailed parametric study on the geometry of ribs to achieve maximum wall temperature and uniform temperature distribution. Since, the conventional chemical batteries are outperformed due to aforementioned issues, several combustion-based micropower generation systems such as micro gas turbine [22], micro thermophotovoltaic generators [23,24], fuel cells [25] and thermoelectric generators [26][27][28][29][30], were recently proposed and investigated. Although, heat engines could be commonly proposed, their significant heat and friction losses due to the presence of moving parts make them impractical for various applications at such small scales because of strong noise and low conversion efficiencies.…”

Section: Introductionmentioning

confidence: 99%

“…A TE based power generator using Silicon-coated catalytic combustor fabricated by Yoshida et al [26] was able to produce 184mW power with 2.8 % conversion efficiency. Shimokuri et al [28] developed a mesoscale vortex combustor integrated with TE modules. Their result suggests that the heat transfer was significantly enhanced due to formation of vortex flow and produced a system efficiency of 3 % with a power output of 18.1 W. Yadav et al [29] used a three-step combustor with a recirculation cup as a heating source.…”

Section: Introductionmentioning

confidence: 99%

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Experimental investigations on a new high intensity dual microcombustor based thermoelectric micropower generator

2018

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A new concept of dual microcombustor based thermoelectric micropower generator with high power density (~0.14 mW/mm 3) and high conversion efficiency (4.66 %) is reported in this work. A new configuration with a dual microcombustor system is experimentally investigated with two thermoelectric modules and operates with liquefied petroleum gas as fuel. The dual microcombustor is fabricated using a rectangular aluminium metal block and detailed investigations on flame stability limits and thermal characteristics were carried out. Dual microcombustor configuration helps to significantly improve the flame stability limits and thermal characteristics over the single combustor configuration due to increased flame-surface interaction and enhanced heat recirculation through solid walls. Maximum power point tracking (MPPT) algorithm is applied to achieve a maximum power output of 4.52 W with a maximum conversion efficiency of 4.66 %. The application of porous media significantly helped improve the upper flame stability limits with a maximum conversion efficiency of 4.32 %, and 4.66 %, at  = 1 and 0.9 respectively at 10 m/s mixture velocity. The system compactness and high output power with significantly improved conversion efficiency shows the possibility of its application in various portable micro-scale power generators for remote, stand-alone, military and aerospace applications.

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Section: Comparison Of Dual and Single Microcombustor Configurationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimental investigations on a new high intensity dual microcombustor based thermoelectric micropower generator

2018

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“…Zhao et al investigated the effects of N 2 and CO 2 dilution on the combustion characteristics of C 3 H 8 /O 2 in a swirl tubular flame burner. In consideration of that the tubular flame is a kind of vortex combustion, the corresponding burner has also been defined as vortex combustor . More specifically, this type of burner is called vortex‐tube combustor in this study.…”

Section: Introductionmentioning

confidence: 99%

An exploration of stabilization mechanisms in a novel vortex‐tube combustor with localized stratified peculiarity

Ren

2020

Int J Energy Res

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Experimental and numerical (via ANSYS FLUENT) studies have been conducted on the combustion stability and stabilization mechanisms in a localized stratified vortex-tube combustor (LSVC) under lean conditions. The stability limit and flame configuration were obtained under different combustion conditions. Combined with the flow field distribution, the formation mechanisms of the local stratification of species and the resultant flame configuration were analyzed. Results show that the local stratification peculiarity is responsible for the dual flame appearance. On the basis of the local stratification of species, the local equivalence ratio is close to stoichiometry in the vicinity of the flame front, while it is above 1.0 in the interior, enabling the achievement of stable combustion at a global equivalence ratio as low as 0.12 in the LSVC. The flow field can help the transport of the reactive species and yields an intensified combustion and a large density gradient. The peak heat release rate (HRR) of 0.5 W/mm 3 in the LSVC is much higher than that of 0.1 W/mm 3 in the rapidly mixed vortex-tube combustor (RMVC) at the global equivalence ratio of 0.6 and the maximum tangential velocity of 26.44 m/s. The flame-vortex interaction theory provides a new perspective to interpret the rapid flame propagation in vortex-tube combustors. Based on the pressure jump theory, the flame speed was obtained via a specific formula closely related to the density gradient and the injection velocity. It turns out that the flame speed in the LSVC is remarkably higher than that in the RMVC at a certain same combustion condition. Moreover, the decrease of local flow velocity resulted from the strong swirl provides a favorable guarantee for the balance with the local flame speed. K E Y W O R D S localized stratification, stability limit, stabilization mechanism, vortex bursting, vortex-tube combustor

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“…A model for tangential injection has also been developed to examine the tubular flame characteristics [9]. A variety of configurations from micro-combustor to large size (12 inch) tubular flame burner [10] have been developed to meet industrial demands, including power generation [11][12][13], emissions reduction [14,15], flame stabilization [4] and flame synthesis [16].…”

Section: Introductionmentioning

confidence: 99%

Response of lean premixed swirl tubular flame to acoustic perturbations

Zhao

et al. 2020

Experimental Thermal and Fluid Science

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This study experimentally examined the response of a lean premixed methane/air swirl tubular flame to the longitudinal acoustic perturbations. Experiments were conducted by varying the acoustic frequency (f0), acoustic power (P0) and inlet air flow rate (QA) to systematically study the acoustic-excited flame dynamics, including the flame stability, flame structure, heat release rate and acoustic pressure fluctuations. The results demonstrated that the lean tubular flame was much sensitive to longitudinal perturbations below 210 Hz. Even at low power of P0, the flame was forced to oscillate intensively when the perturbation was operated in two discontinuous frequency ranges of f0 = 150-200 and f0 = 50-100 Hz, while a weakened oscillation regime was observed in the middle range of f0 =100-150 Hz; a lower frequency (less than 50 Hz) would extinguish the flame. An increase in P0 intensified the flame oscillation under the perturbations of 50-100 Hz, and even resulted in flame lift-off and blow off with f0 between 150 and 200 Hz. In comparison to f0 and P0, the effects of air flow rate (QA) seemed to be weaker. The proper orthogonal decomposition (POD) analysis was performed to interpret the contributions from the mean mode and fluctuating axial and circumferential modes that led to combustion instability. It was found that as the energy fraction of the axial mode exceeded 5.0%, the flame lift-off appeared in the lean swirl tubular configuration.

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Development of a powerful miniature power system with a meso-scale vortex combustor

Cited by 61 publications

References 15 publications

Experimental investigations on a new high intensity dual microcombustor based thermoelectric micropower generator

Experimental investigations on a new high intensity dual microcombustor based thermoelectric micropower generator

An exploration of stabilization mechanisms in a novel vortex‐tube combustor with localized stratified peculiarity

Response of lean premixed swirl tubular flame to acoustic perturbations

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