scholarly journals Energy Harvesting Using Thermocouple and Compressed Air

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6031
Author(s):  
Robert Bayer ◽  
Jiří Maxa ◽  
Pavla Šabacká
Keyword(s):  
Gas Flow ◽  
Temperature Drop ◽  
Compressed Air ◽  
Large Temperature ◽  
Physical Analysis ◽  
Cryogenic Temperatures ◽  
Head Shape ◽  
Available Energy ◽  
Thermoelectric Voltage ◽  
Gas Expansion

In this paper, we describe the possibility of using the energy of a compressed air flow, where cryogenic temperatures are achieved within the flow behind the nozzle, when reaching a critical flow in order to maximize the energy gained. Compared to the energy of compressed air, the energy obtained thermoelectrically is negligible, but not zero. We are therefore primarily aiming to maximize the use of available energy sources. Behind the aperture separating regions with a pressure difference of several atmospheres, a supersonic flow with a large temperature drop develops. Based on the Seebeck effect, a thermocouple is placed in these low temperatures to create a thermoelectric voltage. This paper contains a mathematical-physical analysis for proper nozzle design, controlled gas expansion and ideal placement of a thermocouple within the flow for best utilization of the low temperature before a shockwave formation. If the gas flow passes through a perpendicular shockwave, the velocity drops sharply and the gas pressure rises, thereby increasing the temperature. In contrast, with a conical shockwave, such dramatic changes do not occur and the cooling effect is not impaired. This article also contains analyses for proper forming of the head shape of the thermocouple to avoid the formation of a detached shockwave, which causes temperature stagnation resulting in lower thermocouple cooling efficiency.

Improved MSMGFSK Models Apply to Gas Radiation Heat Transfer Calculation of Exhaust System of TBCC

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Haiyang Hu ◽  
Qiang Wang
Keyword(s):  
Heat Transfer ◽  
Gas Flow ◽  
Thermal Emission ◽  
Radiation Heat Transfer ◽  
Exhaust System ◽  
Combined Cycle ◽  
Large Temperature ◽  
Radiation Heat ◽  
Full Spectrum ◽  
Radiation Emission

The multiscale multigroup full-spectrum k-distribution (MSMGFSK) model was improved to adapt to radiation heat transfer calculations of combustion gas flow field with large temperature and pressure gradient. The improvements in calculation accuracy resulting from new sorting strategy of the spectral absorption coefficients were validated using a series of semi-1D problem in which strong temperature, pressure, and mole fraction inhomogeneities were present. A simpler method to attain compatibility between the MSMGFSK model and the gray-wall radiation emission has been established and validated. Finally, estimates are given for the calculation of wall radiation heat transfer characteristics and thermal emission imaging of the exhaust system of the parallel turbine-based combined cycle (TBCC) engine, using finite volume method (FVM) and ray trace method (RT), respectively.

Semi-Solid Slurry Casting Using Gas Induced Semi-Solid Technique to Enhance the Microstructural Characteristics of Al-4.3Cu Alloy

2019 ◽  
Vol 285 ◽  
pp. 253-258
Author(s):  
M. Abdi ◽  
S.G. Shabestari
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Temperature Drop ◽  
Inert Gas ◽  
Globular Structure ◽  
Cast Sample ◽  
A206 Alloy ◽  
Gas Purging ◽  
Semi Solid ◽  
Conventionally Cast

Semi-solid processing of Al-4.3%Cu (A206) alloy was performed by Gas Induced Semi-Solid (GISS) process in different condition. The flow rate of argon gas, starting temperature for gas purging (the temperature of superheated-melt) and the duration of gas purging were three key process variables which were changed during this investigation. It was found that inert gas purging near liquidus, significantly, led to the microstructural modification from fully dendritic to globular structure. Thermal analysis was successfully implemented through CA-CCTA technique to understand the cause of the microstructure change during GISS process. The results showed that gas purging into the melt leads to temperature drop of the melt to its liquidus just after a few seconds from start of gas purging. In fact, copious nucleation was induced by cooling effect of inert gas bubbles. Microstructural features were characterized in semi-solid as well as on conventionally cast samples. The optimum gas purging temperature, injection time, and inert gas flow rate was determined in semi-solid processing to obtain the best globularity in the microstructure of a long freezing range alloy. However, the microstructure of the conventionally cast sample was fully dendritic with shrinkage which affects the soundness of casting products.

Sensitivity of Thermal Transport in Uranium Dioxide to Fission Gas

2019 ◽  
Author(s):  
Katherine Mitchell ◽  
Hunter Horner ◽  
Alex Resnick ◽  
Jungkyu Park ◽  
Eduardo B. Farfán ◽  
...  
Keyword(s):  
Thermal Resistance ◽  
Uranium Dioxide ◽  
Thermal Transport ◽  
Temperature Drop ◽  
Phonon Transport ◽  
Interfacial Thermal Resistance ◽  
Large Temperature ◽  
Gas Bubble ◽  
Gas Generation ◽  
Fission Gas

Abstract Understanding the effect of fission gas generation on thermal resistance in various nuclear fuels is critical for managing fuel performance. Fission gas in the fuels degrades its thermal properties by altering the lattice vibrations. It results in thermal expansion that increases the thermal resistance and decreases the structural stability of the fuels. In this research, thermal transport in uranium dioxide is studied at a microscopic level when Xe and Kr gasses interact with uranium and oxygen atoms. Reverse non-equilibrium molecular dynamics (RNEMD) is used to calculate the thermal resistances and provide an understanding about the effect of the fission gas release on phonon transport. The results show that the thermal conductivity of uranium dioxide is decreased nearly by 78% by the presence of only one fission gas bubble. The thermal transport in uranium dioxide is shown to become highly diffusive by a single fission gas bubble and a large temperature drop in temperature profiles are observed in all simulation structures with fission gas bubbles. The average interfacial thermal resistance across a fission gas bubble is estimated to be 2.1 × 10−9 Km2/W.

A Pneumatic Multi-Dome Active Energy Harvesting System

2016 ◽  
Author(s):  
Daniel Goodey ◽  
Austin Fidlar ◽  
Varuna Denawakage Don ◽  
Donnie Hudnell ◽  
Ronell Pemberton ◽  
...  
Keyword(s):  
Heavy Traffic ◽  
Compressed Air ◽  
Pneumatic Cylinder ◽  
The Road ◽  
Available Energy ◽  
Road Pavement ◽  
Physical Prototype ◽  
Simulation Testing ◽  
System Data ◽  
Toll Booth

When traveling through heavy traffic, vehicles lose a large amount of their kinetic energy. These losses can be attributed to various sources such as the roll friction of the tires against the road pavement. According to the Federal Highway Administration, there are an average of 304,000 cars a day travelling on the US-75 near the Dallas Fort Worth Arlington area in Texas. With so much available energy being wasted, it is essential to find a different way to harness losses so that they can be recycled. The purpose of this research project is to design a system that will harvest some of this lost energy using a set of pneumatic cylinders built into the road. The cylinders will have a dome shape that extends slightly above the surface of the road. As cars pass over this dome the cylinder will retract and compressed air will be sent through a pneumatic system, to an air tank where it is stored. The energy generated by the air stored in the cylinder can be used to drive a pneumatic motor that can turn a generator. The generator could then be used for multiple purposes such as: charge a battery, power a toll booth or other near highway structures. The compressed air stored in the tank may be used for other applications. This is useful due to the fact that almost every industry from the medical industry to the food industry use compressed air to power their pneumatic tools. The pneumatic cylinder will be used in areas of high traffic such as when a car approaches a toll booth, or entrances and exits of multi-level parking garages. The pneumatic cylinder and the associated air flow system using a CAD and a pneumatic software. The behavior of the system could then be tested and be better understood. After the initial simulation testing, a physical prototype has been built in order to gather practical data that can be compared to the simulations. Based on the gathered data on the prototype an assembly of numerous road rumbles can be built and tested on real streets. It is expected that a high pressure will be built in the tank using the prototype. Once pressure is built in the system data will be generated using various instruments, which will show pressure versus time, and pressure versus number of strokes so that the system can be better understood during the testing period. This data will then be used to determine the efficiency, and viability of the proposed system in generating compressed air as a form energy.

The Flow Characteristics Analysis of Transonic around Delta-Wing to Separate Water from Natural Gas

2012 ◽  
Vol 462 ◽  
pp. 26-32
Author(s):  
Jun Qi Wang ◽  
Yang Yang Zhang
Keyword(s):  
Natural Gas ◽  
Gas Flow ◽  
Delta Wing ◽  
Temperature Drop ◽  
Flow Characteristics ◽  
Attack Angle ◽  
Water Separation ◽  
Process Gas ◽  
Characteristics Analysis ◽  
Expansion Angle

The changes in flow channel area and convergence-expanding nozzle help to flow rate of natural gas to the sound speed, also increase diameter to accelerate flow velocity and finally reach transonic flow condition. At this point, the temperature drop makes saturated water in natural gas condenses into droplets, generates swirl around the delta-wing, realize gas-water separation. This paper concentrates on Flent6.1 software process gas flow around a delta wing simulation, explains expansion angle and attack angle of delta-wing, determines a reasonable delta-wing attack angle is 10°, pipeline expansion angle is 0.29°, and obtains velocity vector, mach number, total pressure, static temperature and other flow field details of the attack angle and expansion angle, which lay foundation for production and application of the technology.

Large temperature drop across the Eocene–Oligocene transition in central North America

Nature ◽  
2007 ◽  
Vol 445 (7128) ◽  
pp. 639-642 ◽  
Author(s):  
Alessandro Zanazzi ◽  
Matthew J. Kohn ◽  
Bruce J. MacFadden ◽  
Dennis O. Terry
Keyword(s):  
North America ◽  
Temperature Drop ◽  
Large Temperature

CFD Simulation of a Coolant Flow and a Heat Transfer in a Pebble Bed Reactor

2008 ◽  
Author(s):  
Wang-Kee In ◽  
Won-Jae Lee ◽  
Yassin A. Hassan
Keyword(s):  
Heat Transfer ◽  
Gas Flow ◽  
Cfd Simulation ◽  
Reverse Flow ◽  
Temperature Drop ◽  
Coolant Flow ◽  
Normal Operation ◽  
Fuel Temperature ◽  
Pebble Bed Reactor ◽  
Detailed Simulation

This CFD study is to simulate a coolant (gas) flow and heat transfer in a PBR core during a normal operation. This study used a pebble array with direct area contacts among the pebbles which is one of the pebbles arrangements for a detailed simulation of PBR core CFD studies. A CFD model is developed to more adequately represent the pebbles randomly stacked in the PBR core. The CFD predictions showed a large variation of the temperature on the pebble surface as well as in the pebble core. The temperature drop in the outer graphite layer is smaller than that in the pebble-core region. This is because the thermal conductivity of graphite is higher than the fuel (UO2 mixture) conductivity in the pebble core. Higher pebble surface temperature is predicted downstream of the pebble contact due to a reverse flow. Multiple vortices are predicted to occur downstream of the spherical pebbles due to a flow separation. The coolant flow structure and fuel temperature in the PBR core appears to largely depend on the in-core distribution of the pebbles.

Heat Transfer and Thermoelectric Voltage at Metallic Point Contacts

1993 ◽  
Vol 115 (3) ◽  
pp. 757-762 ◽  
Author(s):  
P. E. Phelan ◽  
O. Nakabeppu ◽  
K. Ito ◽  
K. Hijikata ◽  
T. Ohmori ◽  
...  
Keyword(s):  
Temperature Drop ◽  
Point Contact ◽  
Thermal Characteristics ◽  
Mean Free Path ◽  
Contact Radius ◽  
Point Contacts ◽  
Plate Temperature ◽  
Thermoelectric Voltage ◽  
The Mean ◽  
Electron Mean Free Path

Metallic point contacts have been extensively studied from the viewpoint of their interesting, and often nonlinear, electrical properties. Their thermal characteristics, however, have largely been ignored, even though they show great potential as microscale temperature sensors. It has been previously demonstrated that when a temperature drop exists across a point contact consisting of two identical metals, a thermoelectric voltage can be generated, provided the mean contact radius is comparable in size to the electron mean free path. In the present experimental study, a point contact is formed by pressing a sharply etched Ag whisker against either an Ag or a Cu flat plate. In addition to confirming the previous results, the feasibility of using such a point contact is demonstrated by calibrating the voltage output against the nondimensionalized plate temperature. Furthermore, the thermoelectric voltage at an Ag–Cu point contact is also presented, showing that a point contact made from dissimiliar metals is even more promising than one made from identical materials. Finally, the point-contact thermal resistance is shown to depend nonlinearly on the electrical resistance, or contact area, and on the temperature drop.

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