Combustion in wavy micro-channels for thermo-photovoltaic applications – Part I: Effects of wavy wall geometry, wall temperature profile and reaction mechanism

The purpose of this research is to evaluate the performance of a novel model that incorporates a thermoelectric generator (TEG) and phase change material (PCM). The proposed model passively generates electricity using waste heat that accumulates at exterior wall surfaces. The main generator is a TEG. To maintain the temperature difference between the two sides of the TEG, PCM is located at its cold side—thus converging the heat transferred into latent heat. The proposed passive generation system is formed into a TEG-PCM block. The block can be stacked to form a wall or inserted into any part of a building that faces the sun. The experiment setup is based on a constant temperature method. The wall temperature profile is set according to solar radiation, convection, and radiative heat transfer. To replicate daily wall temperatures during the experiment, a heat plate is used to match a wall temperature profile. Step control was used for the heating plate. The resulting data shows the average temperature difference between the hot and cold sides of the TEG to be 10-20°C. The peak generated electricity was 0.08 W for a single module.

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Flame Chromatography: Toward Fuel Indexing Based on Multiple Weak Flames in a Meso-Scale Channel With a Prescribed Temperature Profile

ASME 2011 9th International Conference on Nanochannels, Microchannels, and Minichannels, Volume 2 ◽

10.1115/icnmm2011-58291 ◽

2011 ◽

Author(s):

Kaoru Maruta

Keyword(s):

Temperature Profile ◽

Wall Temperature ◽

Wide Temperature Range ◽

Ignition Temperature ◽

Flame Stability ◽

Research Octane Number ◽

Multi Stage ◽

Auto Ignition ◽

First Time ◽

Meso Scale

For understanding flame stability in microcombustor, fundamental studies on the combustion characteristics in a meso-scale channel with a prescribed wall temperature profile have been conducted. Results showed that the existence of dynamic oscillatory flames and weak flames in addition to the normal propagating flames for the first time. It is then recognized that the weak flame phenomena can be applied for examining multi-stage oxidation of hydrocarbon fuels in wide temperature range from 300K up to auto-ignition temperature. Based on the preliminary experiments with various fuels including primary referenced fuel for gasoline, research octane number (RON) of the test fuels can be clearly described by the aspects of the stabilized stationary multiple weak flames. The methodology can be termed “flame chromatography” and it is expected to be applied for fuel indexing of future alternative fuel characterizations.

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Suppression of flame instability by a short catalytic segment on the wall of a micro channel with a prescribed wall temperature profile

Fuel ◽

10.1016/j.fuel.2018.08.025 ◽

2018 ◽

Vol 234 ◽

pp. 1329-1336 ◽

Cited By ~ 20

Author(s):

Shixuan Wang ◽

Linhong Li ◽

Aiwu Fan

Keyword(s):

Temperature Profile ◽

Wall Temperature ◽

Micro Channel ◽

Flame Instability

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Free Convection in an Inclined Square Cavity With Partial Partitions on a Wavy Hot Wall

Volume 1 ◽

10.1115/esda2004-58251 ◽

2004 ◽

Author(s):

M. Belkadi ◽

A. Azzi ◽

O. Imine ◽

L. Adjlout ◽

M. Aounallah ◽

...

Keyword(s):

Heat Transfer ◽

Free Convection ◽

Numerical Study ◽

Wavy Wall ◽

Square Cavity ◽

Inclination Angles ◽

The Mean ◽

Rayleigh Numbers ◽

Partial Partitions ◽

Wall Geometry

In the present investigation, a numerical study of the effect of the hot wavy wall with partial partitions on free convection in an inclined square cavity, differentially heated, was undertaken. This problem is solved by using the partial differential equations which are the equation of mass, momentum, and energy. The tests were performed for different inclination angles, partition lenghts and Rayleigh numbers while the Prandtl number was kept constant. A configuration with three undulations and three partitions has been tested. The results obtained show that the hot wall geometry with partions affects the heat transfer rate in the cavity. The mean Nusselt number decreases notably compared with the heat transfer in the square undulated cavity without partitions.

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Effect of Wall Temperature Profile Inputs on Thermal Hydraulic Characteristics in Long Vertical Steam Generator Tube

SSRN Electronic Journal ◽

10.2139/ssrn.3679529 ◽

2020 ◽

Author(s):

Chaitanya R. Mali ◽

V. Vinod ◽

Ashwin W. Patwardhan

Keyword(s):

Temperature Profile ◽

Steam Generator ◽

Wall Temperature ◽

Hydraulic Characteristics ◽

Steam Generator Tube

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Fully Transient Model of a Hydraulic Accumulator

Volume 7: Fluids Engineering ◽

10.1115/imece2019-11343 ◽

2019 ◽

Author(s):

Filipp Kratschun ◽

Andris Rambaks ◽

Katharina Schmitz

Keyword(s):

Heat Transfer ◽

System Design ◽

Temperature Profile ◽

Gaseous Phase ◽

Wall Temperature ◽

Velocity Profiles ◽

Simulation Approach ◽

Transient Model ◽

Hydraulic Accumulator ◽

Polytropic Exponent

Abstract Hydraulic piston accumulators play a major role especially within the field of stationary hydraulics. The calculation of the amount of hydraulic energy which can be stored in such an accumulator is crucial when it comes to a precise system design. The knowledge of the temperature within the accumulator is required in order to calculate the amount of energy to be stored. This paper presents a simulation approach with the goal to simulate the gaseous phase within a piston accumulator and to present results for the polytropic exponent without conducting costly experiments. The temperature, pressure, density and velocity profiles inside of the gaseous phase as well as the temperature profile inside the boundaries are calculated transiently in order to achieve that goal. The effects of dissipation, heat transfer and transient wall temperature are added to the simulation routine continuously and their effects on the results are discussed in detail.

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