scholarly journals Impact of Heat Shield Thickness on Performance of Roll through Simulation

2019 ◽  
Vol 9 (2) ◽  
pp. 3105-3109
Keyword(s):  
Dissipation Rate ◽  
Heat Dissipation ◽  
Electrical Energy ◽  
Power Input ◽  
Surface Coatings ◽  
Heat Shield ◽  
Steady Temperature ◽  
Time Saving ◽  
Heat Shields ◽  
Stainless Steel 316

Rolls of the packing machine undertakes an imperative job in packing industries. So as to decrease the power input and reducingthe heat dissipation rate, there are numerous methodologies, for example, surface coatings, surface boronizing and with heat shields and so forth. This work is expected to reducethe power contribution to heaters by diminishing the heat dissemination rate utilizing heat shields with simulation of different thicknesses. There is a decrease of dissipation of heat by using Stainless steel 316 Ti (0.7 mm thickness) heat shields and there is a reduction of 13.9% in power input, 28% time saving and14% in heat dissipation rate is noticedwhencompared to standard rolls up to steady surface temperature where there is saving of 198W per hour in power after steady temperature. Hence an attempt is being made for improving results that are obtained from experiments by using simulation through ANSYS steady state thermal analysis. From the results it is inferred that as thickness of heat shield increases the input electrical energy for the heater goes on reducing and results shows that 0.7 mm thickness shield is 4.28% efficient than 0.8 mm heat shield. Further through simulation optimum thickness is was observed. But thickness is restricted to 1mm only because of machine specification complexity. Further the results of simulation for varying thickness are presented with contours of temperature distribution and heat flux.

scholarly journals Estimations on Properties of Redox Reactions to Electrical Energy and Storage Device of Thermoelectric Pipe (TEP) Using Polymeric Nanofluids

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1812
Author(s):  
Qin Gang ◽  
Rong-Tsu Wang ◽  
Jung-Chang Wang
Keyword(s):  
Thermal Conductivity ◽  
Power Density ◽  
Heat Dissipation ◽  
Electrical Energy ◽  
Steel Tube ◽  
Storage Device ◽  
Stainless Steel Tube ◽  
The Novel ◽  
Empirical Formulas ◽  
Dissipative Heat

A thermoelectric pipe (TEP) is constructed by tubular graphite electrodes, Teflon material, and stainless-steel tube containing polymeric nanofluids as electrolytes in this study. Heat dissipation and power generation (generating capacity) are both fulfilled with temperature difference via the thermal-electrochemistry and redox reaction effects of polymeric nanofluids. The notion of TEP is to recover the dissipative heat from the heat capacity generated by the relevant machine systems. The thermal conductivity and power density empirical formulas of the novel TEP were derived through the intelligent dimensional analysis with thermoelectric experiments and evaluated at temperatures between 25 and 100 °C and vacuum pressures between 400 and 760 torr. The results revealed that the polymeric nanofluids composed of titanium dioxide (TiO2) nanoparticles with 0.2 wt.% sodium hydroxide (NaOH) of the novel TEP have the best thermoelectric performance among these electrolytes, including TiO2 nanofluid, TiO2 nanofluid with 0.2 wt.% NaOH, deionized water, and seawater. Furthermore, the thermal conductivity and power density of the novel TEP are 203.1 W/(m·K) and 21.16 W/m3, respectively.

Uncertainty Quantification of Thermocouple Air Temperature Measurement in Highly Radiative Environment: Application to Turbofan Engine Compartment

2016 ◽  
Author(s):  
Y. Sommerer ◽  
V. Drouin ◽  
X. Nicolas ◽  
B. Trouette
Keyword(s):  
Heat Flux ◽  
Temperature Measurement ◽  
Air Temperature ◽  
Data Bank ◽  
Heat Shield ◽  
Engine Compartment ◽  
Heat Shields ◽  
Air Speed ◽  
Thermocouple Temperature ◽  
The Impact

This paper focuses on thermocouple air temperature measurement uncertainty due to the radiative fluxes present in the engine compartment where engine case skin temperature can exceed 900 K. To really measure air temperature, the convective heat flux in the thermocouple bead must be predominant. This is why heat shields are used in order to reduce the radiative heat flux on the bead. However, in engine compartment, the heat shield orientation must be optimized since numerous hot walls surround the thermocouple. In order to evaluate the impact of badly oriented heat shields and to provide a data bank for numerical simulation validations, a heated wind tunnel has been used. It has been shown that the uncertainty on the thermocouple temperature can reach dozens of degrees depending on the air speed and the heat shield orientation. Furthermore a specific 3D thermocouple model has been build and validated by comparison with the lab measurements. Then this thermocouple 3D model has been integrated in the whole engine compartment aero-thermal model in order to quantify the uncertainty of the thermocouple air temperature measurement in the real engine environment.

scholarly journals Investigating green infrastructure as potential medium for ground heat exchangers

2020 ◽  
Vol 205 ◽  
pp. 06013
Author(s):  
Anil Yildiz ◽  
Ross A. Stirling
Keyword(s):  
Soil Temperature ◽  
Green Infrastructure ◽  
Heat Exchangers ◽  
Heat Dissipation ◽  
Power Input ◽  
Atmospheric Conditions ◽  
Heat Rejection ◽  
Capital Costs ◽  
Ground Heat Exchangers ◽  
Heating And Cooling

Space heating and cooling comprises a significant portion of the overall energy consumption. Ground heat exchangers (GHE), are a sustainable alternative to conventional, non-renewably powered heating and cooling systems. Space is a scarce resource in densely urbanised areas, allocating dedicated locations to build GHE systems can result in high initial capital costs and an inflexibility in retrofitting. An alternative solution is to utilise existing, multi-benefit and resilient Sustainable Drainage Systems (SuDS) in cities. An investigation into the feasibility of utilising SuDS as sites for potential GHEs requires an understanding of their thermal and hydrological behaviour and boundary conditions. This study utilises a heavily-instrumented, vegetated lysimeter setup, exposed to atmospheric conditions, to test a pilot-scale SuDS heat exchanger. Heat rejection into the substrate of a SuDS has been simulated with the application of heat via voltage-controlled heating cables at a depth of 850 mm for 72-hour durations (at three different power inputs) with 96-hours between each power input. These heat dissipation periods are reflected in measured soil temperature profiles. Volumetric water content, matric suction, soil temperature and heat flux are monitored at various locations in the lysimeter. A finite difference modelling scheme has been developed to simulate the variation in soil temperature due to heat rejection.

Energy Harvesting and Energy Conversion Devices Using Thermoelectric Materials

2015 ◽  
pp. 198-253 ◽  
Author(s):  
Mihail O. Cernaianu ◽  
Aurel Gontean
Keyword(s):  
Energy Harvesting ◽  
Heat Dissipation ◽  
Waste Heat ◽  
Electrical Energy ◽  
Electronic System ◽  
Rechargeable Batteries ◽  
Energy Harvesting System ◽  
Condition Monitoring System ◽  
Energy Conversion Devices ◽  
Sustainable Power

The authors propose in this chapter an original, self-sustainable, power supply system for wireless monitoring applications that is powered from an energy harvesting device based on thermoelectric generators (TEGs). The energy harvesting system's purpose is to gather the waste heat from low temperature sources (<90°C), convert it to electrical energy and store it into rechargeable batteries. The energy harvesting system must be able to power a so-called condition monitoring system (CMS) that is used for the monitoring of heat dissipation equipment. The setup used for measurements (including mechanical details) and the experiments are described along with all the essential results of the research. The electronic system design is emphasized and various options are discussed.

FEM-Simulation of the electrode temperature distribution and crater formation. Part II: Arc and glow phases of an electrical discharge

2004 ◽  
Vol 120 ◽  
pp. 439-446
Author(s):  
F. Soldera ◽  
F. Mücklich
Keyword(s):  
Glow Discharge ◽  
Temperature Increase ◽  
Fem Simulation ◽  
Electrical Energy ◽  
Power Input ◽  
Heat Diffusion ◽  
Large Area ◽  
Electrode Gap ◽  
Heat Diffusion Equation ◽  
Calorimetric Investigations

A FEM model was developed to simulate the temperature increase in the material due to the power input of a discharge, which is composed of three different phases: breakdown, arc and glow discharge. In this paper the results for the arc and the glow discharge are dealt with. The model is based on the heat diffusion equation and considers phase transformations. A molten and an evaporated region were simulated and their dimensions were compared with the dimensions of craters made on polished Pt-samples (in air at 1 and 9 bar, with electrode gap of 2 mm). The electrical energy was calculated with the voltage and current curves. Using results of calorimetric investigations published in literature, the fraction of energy absorbed by the electrodes was estimated. The best results of the simulated regions for the arc were obtained for the lower values of energy input. For the largest energies, the evaporated region is overestimated. The molten and evaporated regions are hemispherical and deeper than the craters, which present a flat shape. The glow discharge produces a temperature increase in the electrode of only 1.8 degree, because the energy is distributed in a large area of the cathode.

scholarly journals Study of Manufacturing Process of Holes in Aeroengine Heat Shield

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Anyuan Jiao ◽  
Weijun Liu
Keyword(s):  
Cutting Temperature ◽  
Dimensional Accuracy ◽  
Aircraft Engine ◽  
Heat Shield ◽  
Drilling Process ◽  
High Plasticity ◽  
Processing Efficiency ◽  
Technical Parameters ◽  
Nickel Based Superalloy ◽  
Heat Shields

The nickel-based superalloy GH3128 with high plasticity, high long-lasting creep strength, good resistance to oxidation and stamping, and good welding performance is widely used in aircraft engine heat shields. The many holes that need to be machined on the heat shield are not only small in diameter but also dense, and GH3128 as a typical hard-to-process material has the problems of large cutting force, high cutting temperature, and serious hardening. Therefore, poor dimensional accuracy and residual burrs have become the main factors that limit the processing efficiency and processing quality. So, a novel combination of manufacturing processes was proposed. Firstly, laser cutting technology was used to process the base hole in a GH3128 plate, followed by reaming, and finally, using a magnetic abrasive finishing effector to remove burrs formed during the first two steps. The whole drilling process of the heat shields fully meets the requirements of the technical parameters. This study provides new reference for manufacturing the holes of a heat shield and other similar porous parts.

Enhanced Energy Efficiency of Light Grid System with Optimized System Design and Recycling with Thermoelectric Platform

2021 ◽  
Vol 21 (3) ◽  
pp. 1927-1931
Author(s):  
Jae-Hoon Ji ◽  
Hong-Tae Kim ◽  
Sung-Jin Kim ◽  
Masao Kamiko ◽  
Jung-Hyuk Koh
Keyword(s):  
Energy Efficiency ◽  
High Power ◽  
Heat Dissipation ◽  
Electrical Energy ◽  
Grid System ◽  
Optical Energy ◽  
Thermoelectric Modules ◽  
Dissipation Structure ◽  
High Power Led ◽  
Effective Design

In this work, a light grid system with a high-power LED chip was manufactured and employed to analyze the energy efficiency of output optical energy. The high-power LED system based on thermoelectric modules, a heat dissipation structure and optical transmission system with an optical fiber were optimally combined and designed, which increased the efficiency of light grid system. Additionally, by introducing an effective design for the heat dissipation structure, the output optical energy and recycled electrical energy were increased. The recycled energy through optimized heat dissipation structure was 1.94 W, and the system efficiency of designed light grid system is more than 50%. In this research, we intensively studied the energy efficiency of a light grid system as well as the recycling of thermal energy through thermoelectric modules.

Ocean Turbulent Mixing in Northern Bohai Strait, China

2013 ◽  
Author(s):  
Shu-xiu Liang ◽  
Zhao-chen Sun ◽  
Song-lin Han ◽  
Hong-qiang Yin ◽  
Bo Bai
Keyword(s):  
Turbulent Mixing ◽  
Yellow Sea ◽  
Dissipation Rate ◽  
Bohai Sea ◽  
Heat Dissipation ◽  
Strong Mixing ◽  
Observation Data ◽  
Diffusivity Coefficient ◽  
Division Line ◽  
Bohai Strait

The measurements of ocean microstructure through which ocean internal mixing mechanism is revealed are taken more often recently. Free-falling turbulence microstructure profiler TurboMAP-9 is used to take a field observation on the area of northern Bohai Strait. 13 stations distributed in Bohai Sea, Yellow Sea and the “division line” between them are measured. Turbulent mixing characteristics of northern Bohai Strait for different seasons are described by analyzing the observation data of ocean turbulence microstructure profile. The results show that the northern Bohai Strait is a strong mixing area during non-stratification period. Turbulent energy dissipation rate ε of winter is bigger than that of autumn and it is strongest near the bottom layers which is in the order of 10−5W/kg. Heat dissipation rate χθ is in the same order of 10−6–10−5°C2/s in autumn as ε and 2–3 orders smaller than ε in winter. Thermal diffusivity coefficient kθ is a little bigger than turbulent mixing rate kρ in autumn and 1–2 orders smaller than kρ in winter. Both the kρ and kθ along the “division line” of Bohai Sea and Yellow Sea are bigger than that of the Bohai Sea and Yellow Sea. Base on the measured data and the analysis, heat dissipation rate and thermal dispersion coefficient can change 2–3 orders in non-stratification seasons which should be paid much attention to, especially for ocean model parameterization and pollutant discharge modeling.

scholarly journals Characterization of Spatter and Sublimation in Alloy 718 during Electron Beam Melting

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 5953
Author(s):  
Ahmad Raza ◽  
Eduard Hryha
Keyword(s):  
Electron Beam ◽  
Electron Beam Melting ◽  
Elevated Temperatures ◽  
Ion Beam ◽  
High Vacuum ◽  
Alloying Elements ◽  
Heat Shield ◽  
Alloy 718 ◽  
Feedstock Powder ◽  
Heat Shields

Due to elevated temperatures and high vacuum levels in electron beam melting (EBM), spatter formation and accumulation in the feedstock powder, and sublimation of alloying elements from the base feedstock powder can affect the feedstock powder’s reusability and change the alloy composition of fabricated parts. This study focused on the experimental and thermodynamic analysis of spatter particles generated in EBM, and analyzed sublimating alloying elements from Alloy 718 during EBM. Heat shields obtained after processing Alloy 718 in an Arcam A2X plus machine were analyzed to evaluate the spatters and metal condensate. Comprehensive morphological, microstructural, and chemical analyses were performed using scanning electron microscopy (SEM), focused ion beam (FIB), and energy dispersive spectroscopy (EDS). The morphological analysis showed that the area coverage of heat shields by spatter increased from top (<1%) to bottom (>25%), indicating that the spatter particles had projectile trajectories. Similarly, the metal condensate had a higher thickness of ~50 μm toward the bottom of the heat shield, indicating more significant condensation of metal vapors at the bottom. Microstructural analysis of spatters highlighted that the surfaces of spatter particles sampled from the heat shields were also covered with condensate, and the thickness of the deposited condensate depended on the time of landing of spatter particles on the heat shield during the build. The chemical analysis showed that the spatter particles had 17-fold higher oxygen content than virgin powder used in the build. Analysis of the metalized layer indicated that it was formed by oxidized metal condensate and was significantly enriched with Cr due to its higher vapor pressure under EBM conditions.

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