scholarly journals THE MAPPING OF SUBSURFACE TEMPERATURE AND STUDY OF GEOTHERMAL GRADIENT ANOMALY IN THE DISCHARGE AREA IN NORTH SULAWESI

2020 ◽  
Vol 6 (1) ◽  
pp. 1-4
Author(s):  
Donny Royke Wenas ◽  
Cyrke A.N. Bujung
Keyword(s):  
Heat Source ◽  
Geothermal Gradient ◽  
Heat Propagation ◽  
Source Zone ◽  
Maximum Temperature ◽  
Heat Transmission ◽  
North Sulawesi ◽  
Subsurface Layers ◽  
Remote Sensing Techniques ◽  
Location Mapping

The aim of this research is to measure and mapping the temperature distribution in several subsurface layers in the manifestation of geothermal warm ground and steaming ground, and analyze the geothermal subsurface gradient, to determine the heat source zone, and the pattern and direction of heat flow from subsurface to surface in  Hydrothermal area of Minahasa Indonesia. The method used is direct measurement in the field. To determine the coordinates of geothermal manifestations and location mapping, using remote sensing techniques. The results showed that at a depth of 200 cm the temperature reaches 102 0C and the heat source comes from the northeast and from the south. At a depth of 150 cm the temperature varies from 52 to 100 0C with an even distribution in almost every direction. At a depth of 50 to 100 cm the maximum temperature reaches 98 0C with heat propagation starting to concentrate then northeast, and then out to the surface in the northeast. The pattern of heat transmission is almost linear along with the geothermal gradient.

scholarly journals Sensing of Heat Source in a Deep Layer by Considering Heat Propagation

2018 ◽  
Vol 7 (3) ◽  
pp. 229-235 ◽  
Author(s):  
Yukiko Osawa ◽  
Seiichiro Katsura
Keyword(s):  
Heat Source ◽  
Deep Layer ◽  
Heat Propagation

A Comparative Study Between Selective Laser Melting and Electron Beam Additive Manufacturing Based on Thermal Modeling

2018 ◽  
Author(s):  
M. Shafiqur Rahman ◽  
Paul J. Schilling ◽  
Paul D. Herrington ◽  
Uttam K. Chakravarty
Keyword(s):  
Electron Beam ◽  
Additive Manufacturing ◽  
Heat Source ◽  
Selective Laser Melting ◽  
Thermal Modeling ◽  
Maximum Temperature ◽  
Full Density ◽  
Rate Variation ◽  
Laser Melting ◽  
Melt Pool

Selective Laser Melting (SLM) and Electron Beam Additive Manufacturing (EBAM) are two of the most promising additive manufacturing technologies that can make full density metallic components using layer-by-layer fabrication methods. In this study, three-dimensional computational fluid dynamics models with Ti-6Al-4V powder were developed to conduct numerical simulations of both the SLM and EBAM processes. A moving conical volumetric heat source with Gaussian distribution and temperature-dependent thermal properties were incorporated in the thermal modeling of both processes. The melt-pool geometry and its thermal behavior were investigated numerically and results for temperature profile, cooling rate, variation in specific heat, density, thermal conductivity, and enthalpy were obtained with similar heat source specifications. Results obtained from the two models at the same maximum temperature of the melt pool were then compared to describe their deterministic features to be considered for industrial applications. Validation of the modeling was performed by comparing the EBAM simulation results with the EBAM experimental results for melt pool geometry.

scholarly journals Thermal Evolution of the Nucleus of the Comet 67P for 120 Years: Numerical Simulations

2018 ◽  
Vol 27 (1) ◽  
pp. 175-182 ◽  
Author(s):  
Andrey V. Rusol ◽  
Vera A. Dorofeeva
Keyword(s):  
Thermal Evolution ◽  
Rotation Axis ◽  
Cometary Nucleus ◽  
Heat Propagation ◽  
The Sun ◽  
Rock Body ◽  
Cometary Nuclei ◽  
Orbital Cycles ◽  
Subsurface Layers ◽  
Comet 67P

Abstract The purpose of this paper is to estimate to what temperatures and to what depth the outer layers of the cometary nuclei are heated for several dozen revolutions around the Sun, and what changes in the composition of the volatiles occur in this case. This is important because it is not clear how much the experimentally obtained results on the composition of cometary comes depend on how long the comet is in the current orbit. Our approach to this problem is based on using 3D model of the geometry and dynamics of a cometary nucleus that takes into account the diurnal rotation and orientation of the rotation axis relative to the Sun to simulate the irradiance to take value of temperature the surface of the nucleus and 1D thermal model of the porous ice-rock body. The results of the numerical simulation of heat propagation in the subsurface layers of some points the MA’AT region of the 67P core, obtained for the 20 orbital cycles (close to 130 years), are presented in this paper.

Optical Effects Induced by the Multilayer Nature of SOI Films During Transient Thermal Processing with a Radiant Line Heat Source.

1990 ◽  
Vol 201 ◽  
Author(s):  
Peter Y. Wong ◽  
Ioannis N. Miaoulis ◽  
P. Zavracky
Keyword(s):  
Heat Source ◽  
Radiation Effects ◽  
Silicon Oxide ◽  
Silicon Film ◽  
Radiation Heat Transfer ◽  
Linear Increase ◽  
Maximum Temperature ◽  
Line Heat Source ◽  
Silicon Oxide Layer ◽  
Optical Effects

AbstractRadiation heat transfer has been found to have the greatest Impact on the quality of the thin recrystalllzed silicon film during zone-melting recrystallizatlon (ZMR) processing. This study focused on the radiation effects during ZMR with an Infrared radiant line heat source such as a graphite strip heater. The multilayer nature of the capped sllicon-on-tnsulator (SOI) structure Induces complex optical effects which affect the temperature distribution during processing. A two dimensional numerical model of the ZMR process has been developed using a finite difference scheme. The effect of the radiant line heat source’s emission into the wafer has been modeled with a matrix method using Fresnel coefficients. A numerical parametric study was conducted to observe the effects of varying the thickness of the different layers In a capped SOI wafer on the maximum temperature and melt width attained. Results indicate that the variation of either the capping or insulating silicon oxide layer causes significant fluctuations of the reflectivity and temperature profile of the film. Increasing the thickness of the Si layer results in a nearly linear increase in temperature and melt width after complete melting. Layering schemes that are sensitive to small variations In thickness that may result in large changes in reflectivity were Identified.

Numerical Evaluation of Multiple Phase Change Materials for Pulsed Electronics Applications

2016 ◽  
Author(s):  
David Gonzalez-Nino ◽  
Lauren M. Boteler ◽  
Dimeji Ibitayo ◽  
Nicholas R. Jankowski ◽  
Pedro O. Quintero
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Source ◽  
Phase Change ◽  
Phase Change Materials ◽  
High Energy ◽  
Heat Of Fusion ◽  
Maximum Temperature ◽  
Conductivity Enhancement ◽  
Fast Transient

A simple and easy to implement 1-D heat transfer modeling approach is presented in order to investigate the performance of various phase change materials (PCMs) under fast transient thermal loads. Three metallic (gallium, indium, and Bi/Pb/Sn/In alloy) and two organic (erythritol and n-octadecane) PCMs were used for comparison. A finite-difference method was used to model the transient heat transfer through the system while a heat integration or post-iterative method was used to model the phase change. To improve accuracy, the material properties were adjusted at each iteration depending on the state of matter of the PCM. The model assumed that the PCM was in direct contact with the heat source, located on the top of the chip, without the presence of a thermal conductivity enhancement. Results show that the three metallic PCMs outperform organic PCMs during fast transient pulses in spite of the fact that two of the metallic PCMs (i.e. indium and Bi/Pb/Sn/In) have considerably lower volumetric heats of fusion than erythritol. This is due to the significantly higher thermal conductivity values of metals which allow faster absorption of the heat energy by the PCM, a critical need in high-energy short pulses. The most outstanding case studied in this paper, Bi/Pb/Sn/In having only 52% of erythritol’s heat of fusion, showed a maximum temperature 20°C lower than erythritol during a 32 J and 0.02 second pulse. This study has shown thermal buffering benefits by using a metallic PCM directly in contact with the heat source during short transient heat loads.

scholarly journals The Study of the Electrospark Coating Effect on the Heat Removal Property of Hard Alloy

2020 ◽  
pp. 133-143
Author(s):  
Yaroslav A. Vostrikov ◽  
Sardana A. Sleptsova
Keyword(s):  
Hard Alloy ◽  
Protective Coating ◽  
Heat Removal ◽  
Front Surface ◽  
Heat Propagation ◽  
Cutting Edge ◽  
Maximum Temperature ◽  
Thermal Imager ◽  
Surface Cooling ◽  
Electrospark Coating

The effect of a protective coating on the heat removal properties of a cutting plate made of VK8 tungsten-containing hard alloy has been studied. The article provides a sequence of measurements made by a thermal imager and a thermograph to install a mechanism for heat removal by a protective coating. The factors affecting the fault in temperature measurements in a static experiment by means of a thermal imager are described. The time to maximum temperature transferred from the heated counterbody to the hard alloy with and without coating has been obtained. The exposure time of the maximum temperature transmitted from the counterbody to the alloys under study has been fixed. It has been demonstrated that a multilayer electrospark coating based on Ni, Cu, Fe, Cr, W reduces the maximum temperature under the same test conditions by 42%, while the surface cooling rate at the point close to the cutting edge increases by 53%. The data obtained show the effect of the protective coating on the heat removal property of the hard alloy. The time of heat propagation over the entire surface of the test sample and the cooling time have been studied by means of a thermograph. There is a temperature difference of 103°С for the alloy without coating that has been calculated simultaneously between the points on the cutting edge and at a distance of 2 mm lower along the front surface, while for the alloy with a protective coating the difference was 79°С, it is less by 24%. The thermograms of alloys with and without coating are clearly shown at time to maximum temperature on the surface. The work of the coating to remove heat from the point of contact with the heated counterbody has been proven, and the heat removal property is explained by the composition of the coating obtained by electrospark alloying with electrodes based on Cu, Ni, Fe, W, and Cr

scholarly journals Experimental and Techno-Economic Analysis of Solar-Geothermal Organic Rankine Cycle Technology for Power Generation in Nepal

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Suresh Baral
Keyword(s):  
Power Generation ◽  
Heat Source ◽  
Power Output ◽  
Solar Collector ◽  
Hot Spring ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Maximum Temperature ◽  
Working Fluid ◽  
Working Fluids

The current research study focuses on the feasibility of stand-alone hybrid solar-geothermal organic Rankine cycle (ORC) technology for power generation from hot springs of Bhurung Tatopani, Myagdi, Nepal. For the study, the temperature of the hot spring was measured on the particular site of the heat source of the hot spring. The measured temperature could be used for operating the ORC system. Temperature of hot spring can also further be increased by adopting the solar collector for rising the temperature. This hybrid type of the system can have a high-temperature heat source which could power more energy from ORC technology. There are various types of organic working fluids available on the market, but R134a and R245fa are environmentally friendly and have low global warming potential candidates. The thermodynamic models have been developed for predicting the performance analysis of the system. The input parameter for the model is the temperature which was measured experimentally. The maximum temperature of the hot spring was found to be 69.7°C. Expander power output, thermal efficiency, heat of evaporation, solar collector area, and hybrid solar ORC system power output and efficiency are the outputs from the developed model. From the simulation, it was found that 1 kg/s of working fluid could produce 17.5 kW and 22.5 kW power output for R134a and R245fa, respectively, when the geothermal source temperature was around 70°C. Later when the hot spring was heated with a solar collector, the power output produced were 25 kW and 30 kW for R134a and R245fa, respectively, when the heat source was 99°C. The study also further determines the cost of electricity generation for the system with working fluids R134a and R245fa to be $0.17/kWh and $0.14/kWh, respectively. The levelised cost of the electricity (LCOE) was $0.38/kWh in order to be highly feasible investment. The payback period for such hybrid system was found to have 7.5 years and 10.5 years for R245fa and R134a, respectively.

Voiding Effects on the Thermal Response of Metallic Phase Change Materials Under Pulsed Power Loading

2017 ◽  
Author(s):  
David Gonzalez-Nino ◽  
Lauren M. Boteler ◽  
Nicholas R. Jankowski ◽  
Dimeji Ibitayo ◽  
Pedro O. Quintero
Keyword(s):  
Silicon Nitride ◽  
Heat Source ◽  
Phase Change ◽  
Phase Change Materials ◽  
Cooling System ◽  
Thermal Response ◽  
Metallic Phase ◽  
Maximum Temperature ◽  
Before And After ◽  
Power Loading

Metallic phase change materials (PCMs) have been demonstrated as an excellent alternative to act as a passive cooling system for pulse power applications. The possibility of integrating metallic PCMs, directly on top of a heat source, reducing the thermal resistance between the device and the cooling solution, could result in a significant improvement in thermal management for transient applications. However, the effectiveness of this method of implementation will depend on the quality of the interface between the metallic PCM and the heat source. For this work, a metallic PCM (49Bi/18Pb/12Sn/21In-Bi/Pb/Sn/In for simplicity) was placed directly on top of a device that has a layer of silicon nitride on the top. The device was pulsed with powers of 40W – 160W (84W/cm2 – 338W/cm2) with a 20 ms duration. After reaching the maximum power, the device was pulsed for a second cycle, and the temperature profiles were compared. Micrographical inspections, at the interlayer between the silicon nitride and metallic PCM, were performed before and after the pulses and compared. A maximum temperature of ≈20–25% higher was observed in the performance (at 80W) after pulse cycling. A visual inspection at the mating surfaces, between the metallic PCM and device, showed a clear difference between the contact surfaces before and after pulses. Significant voiding at the PCM interfacial layer was observed after cyclic loading which is believed to be the cause of the recorded increment in maximum temperature.

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