Uninterrupted self‐generation thermoelectric power device based on the radiative cooling emitter and solar selective absorber

Micro thermoelectric power device (MTPD) is used to supplying lasting and stable electric energy for Micro-electro-mechanical systems (MEMS). MTPD mainly includes three parts: micro thermoelectric generator, heat source and sink. To get highest energy density, simulation model for MTPD was built up and optimized. Heat source is an important part of MTPD and micro combustor is the ideal heat source for the device, which is used to supply lasting energy for MTPD. Based upon, several types of MTPD with different micro combustors was designed and tested. Some MTPDs with different design was tested. For example, MTPD with diffuse combustor and that of with premixed combustor, MTPD with quartz combustor and metal combustor, MTPD with liquid fuel and gas fuel, and comparison were done correspondingly. Through a series of experiments, some conclusions were drawn.

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Thermoelectric properties of III-nitrides and III-oxynitrides prepared by reactive rf-sputtering: targetting a thermopower device

MRS Proceedings ◽

10.1557/proc-743-l6.11 ◽

2002 ◽

Vol 743 ◽

Author(s):

S. Yamaguchi ◽

Y. Iwamura ◽

A. Yamamoto

Keyword(s):

Radio Frequency ◽

Thermoelectric Power ◽

Thermoelectric Properties ◽

Power Factor ◽

Rf Sputtering ◽

Power Device ◽

Nitride Semiconductors ◽

Radio Frequency Sputtering ◽

Maximum Value ◽

Maximum Power Factor

ABSTRACTWe have studied thermoelectric properties of III-nitrides of Al1-xInxN and III-oxynitrides of Al1-xInxOsNt and InOsNt prepared by radio-frequency sputtering with the aim of fabricating a thermoelectric power device based on III-nitride semiconductors. For Al0.55In0.45N, the maximum value of power factor was 3.63×10−4 W/mK2 at 873K. For Al0.02In0.98O1.14N0.49 and Al0.14In0.86O1.30N0.67, the maximum power factor was 2.82×10−4 W/mK2 and 4.73×10−4 W/mK2 at 873 K, respectively. For InO0.82N0.86, it was 3.75×10−4 W/mK2 at 973 K.

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Thermoelectric power generator

AccessScience ◽

10.1036/1097-8542.690900 ◽

2015 ◽

Keyword(s):

Thermoelectric Power ◽

Power Generator ◽

Thermoelectric Power Generator

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Saturation mechanism and generated viscosity in gravito-turbulent accretion disks

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038023 ◽

2020 ◽

Vol 640 ◽

pp. A53

Author(s):

L. Löhnert ◽

S. Krätschmer ◽

A. G. Peeters

Keyword(s):

Growth Rate ◽

Numerical Simulations ◽

Accretion Disks ◽

Gravitational Instability ◽

Turbulent Viscosity ◽

Radial Distance ◽

Maximum Growth ◽

Wave Number ◽

Radiative Cooling ◽

Mixing Length

Here, we address the turbulent dynamics of the gravitational instability in accretion disks, retaining both radiative cooling and irradiation. Due to radiative cooling, the disk is unstable for all values of the Toomre parameter, and an accurate estimate of the maximum growth rate is derived analytically. A detailed study of the turbulent spectra shows a rapid decay with an azimuthal wave number stronger than ky−3, whereas the spectrum is more broad in the radial direction and shows a scaling in the range kx−3 to kx−2. The radial component of the radial velocity profile consists of a superposition of shocks of different heights, and is similar to that found in Burgers’ turbulence. Assuming saturation occurs through nonlinear wave steepening leading to shock formation, we developed a mixing-length model in which the typical length scale is related to the average radial distance between shocks. Furthermore, since the numerical simulations show that linear drive is necessary in order to sustain turbulence, we used the growth rate of the most unstable mode to estimate the typical timescale. The mixing-length model that was obtained agrees well with numerical simulations. The model gives an analytic expression for the turbulent viscosity as a function of the Toomre parameter and cooling time. It predicts that relevant values of α = 10−3 can be obtained in disks that have a Toomre parameter as high as Q ≈ 10.

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