Analytical and Experimental Study to Predict Radiated Heat Power Between a Satellite and Thermal Shroud

2014 ◽  
Author(s):  
Daniel T. Schwendtner ◽  
M. Ruhul Amin ◽  
David M. Klumpar
Keyword(s):  
Operating Conditions ◽  
Vacuum System ◽  
Maximum Output ◽  
Heat Power ◽  
Thermal Vacuum ◽  
Small Satellites ◽  
Laboratory Setup ◽  
System A ◽  
Concentric Cylinders ◽  
Small Form Factor

Nanosatellites, a class of small satellites, are becoming increasingly popular because of their small form factor and many other attractive features. In the process of qualifying nanosatellites for space readiness, their thermal behavior can be investigated in a laboratory setup using a thermal vacuum system to mimic orbital conditions. For these reasons, a thermal vacuum system suited specifically for nanosatellites was desired for performing thermal vacuum testing. Analytical calculations and laboratory testing were performed as part of the design of this thermal vacuum system. A set of simultaneous equations was solved using the LU Decomposition method to find the radiosities of several surfaces in an enclosure. The radiosities along with their respective view factors were then used to solve for the heat power required to heat and cool the thermal shroud under steady state conditions at the most extreme operating conditions expected. The analysis was performed on a system of three concentric cylinders of varying heights: the outer being the vacuum chamber wall, the middle the thermal shroud inside the chamber, and the inner the satellite. Under the most extreme operating conditions expected, the thermal shroud was cooled to −40°C and the satellite heated to 80°C during satellite cooling and the reverse during satellite heating. All surfaces in the enclosure were assumed to be diffuse, grey, opaque and isothermal. The thermal shroud was separated into two surfaces: the cylindrical shroud body and the shroud top disc. From the analytical results, the expected heating power for the shroud body was found to be 704.0 Watts, and 229.8 Watts for the shroud top. During cooling, where the temperatures were reversed, the expected heat power for the shroud body was calculated as −685.5 Watts, and −220.9 Watts for the shroud top. An experimental setup was tested under similar conditions as a comparison and as a method to validate the thermal shroud design and the analytical calculations. The shroud body and top heaters were selected to output 750 Watts and 230 Watts, respectively, and were driven at their maximum output, with the satellite held at −40°C. The shroud reached 80°C with no difficulty, indicating that the analytical calculations had correctly predicted the required heat power and that the design of the thermal shroud was capable of supporting testing under the most extreme conditions expected.

Optimization of a Sintering Waste Heat Power Unit

2014 ◽  
Vol 1008-1009 ◽  
pp. 897-900
Author(s):  
Xue Min Gong ◽  
Jiu Lin Yang ◽  
Chen Wang
Keyword(s):  
Power Generation ◽  
Power Unit ◽  
Waste Heat ◽  
Steam Pressure ◽  
Operating Conditions ◽  
Parameters Optimization ◽  
Heat Power ◽  
Optimal Value ◽  
Generation Capacity ◽  
Main Steam

An optimization was performed for a sintering waste heat power unit with all data obtained in the site and under the unit normal operating conditions. The physical and mathematical model for the process of cooling and generation is established, which makes the net power generation as an objective function of the cooling machine imported ventilation, the thickness of sinter and the main steam pressure. Optimizing for single parameter, we found that each parameter had an optimal value for the system. In order to further optimize the system's operating parameters, genetic algorithm was used to make the combinatorial optimization of the three parameters. Optimization results show that power generation capacity per ton is increased by13.10%, and net power generation is increased by 16.17%. The optimization is instructive to the operation of sintering waste heat power unit.

Design of Vacuum System of Steam Jet Bursting Unit for Chestnut Shell

2011 ◽  
Vol 291-294 ◽  
pp. 1685-1688
Author(s):  
Xi Nan Dang ◽  
Qiao Fu Chen ◽  
Li Jun Yang
Keyword(s):  
Energy Consumption ◽  
Vacuum System ◽  
Jet Pump ◽  
Waste Gas ◽  
System A ◽  
Start Up ◽  
Chestnut Shell ◽  
Bursting Process

According to the vacuum bursting process for fresh chestnut shell and requirements for relevant vacuum system, a vacuum system of steam jet pump was designed with a start-up jet pump attached to it. Of which the waste gas from ejector was used for reheating in the bursting process to lead the vacuum bursting unit to run more reliably and stably with efficiency improved and energy consumption reduced. The rate of bursting came up to 95% in the process test.

scholarly journals Determining the environmental indicators for vehicles of different categories in relation to CO2 emission based on road tests

2017 ◽  
Vol 170 (3) ◽  
pp. 66-72
Author(s):  
Jerzy MERKISZ ◽  
Łukasz RYMANIAK
Keyword(s):  
Co2 Emissions ◽  
Operating Time ◽  
Environmental Indicators ◽  
Operating Conditions ◽  
Si Engine ◽  
Propulsion Systems ◽  
System A ◽  
In Series ◽  
Series Configuration ◽  
Ci Engine

The article discusses the possibility of determining the environmental indicators for vehicles of different categories in relation to CO2 emissions. These are called toxicity indicators because they concern the compounds: CO, THC and NOx. Three Euro V compliant vehicles with different propulsion systems types were used for the study: a 0.9 dm3 urban passenger car with a SI engine and a start-stop system, a 2.5 dm3 off-road vehicle with a CI engine, and a city bus with a hybrid drive system in series configuration and a CI engine with a displacement of 6.7 dm3. Measurements were made in actual operating conditions in the Poznan agglomeration using a portable emissions measurement system (PEMS). The paper presents the characteristics of the operating time shares of vehicles and propulsion systems as well as CO2 emissions depending on the engine load and crankshaft rotational speed for individual vehicles. The determined toxicity indicators allowed to indicate their usefulness, to make comparisons between tested vehicles, and to identify directions for further work on the application and interpretation of these indicators.

scholarly journals PROFESSIONAL RISKS TO HEALTH OF THE PERSONNEL OF EXIT BRIGADES OF SERVICE OF THE FIRST HELP

2021 ◽  
Vol 21 (4) ◽  
pp. 17-23
Author(s):  
V. O. Krasovskij ◽  
L. M. Karamova ◽  
G. R. Basharova
Keyword(s):  
Operating Conditions ◽  
Muscular System ◽  
System A ◽  
The Given

Clause analyzes the reasons of professional risks for health of the personnel of exit brigades of the first help. Clinical and hygienic researches in regional substation of a megacity have shown that in labour activity of these workers it is necessary to consider as leading professional harm action of transport vibration. The given circumstance and other reasons provide professional risks of development of illnesses of cardiovascular, bone-muscular system, a gastroenteric path. The interdepartmental complex of actions on improvement of operating conditions of the exit personnel is offered.

Defect Detection in an Annular Swirl-Burner-Array by Optical Measuring Exhaust Gases

2016 ◽  
Author(s):  
Henrik von der Haar ◽  
Ulrich Hartmann ◽  
Christoph Hennecke ◽  
Friedrich Dinkelacker ◽  
Joerg R. Seume
Keyword(s):  
Power Distribution ◽  
Measurement Techniques ◽  
Aircraft Engine ◽  
Operating Conditions ◽  
Maximum Output ◽  
Aircraft Engines ◽  
Combustion Chambers ◽  
Scaled Model ◽  
Ongoing Research ◽  
Exhaust Gases

Defects in combustion chambers of aircraft engines might have an impact on the reliability of the downstream turbine and the machine’s performance. Detecting failures in the combustion chamber of an aircraft engine during operation may improve the resource management and the availability of the system. Aim of the ongoing research project is to find an approach to evaluate the state of the jet engine by analyzing the temperature and emissions field in the exhaust jet. This investigation is part of the collaborative research center SFB 871. The SFB 871 deals with the improvement of the regeneration process of complex capital goods such as aircraft engines. Maintenance, repair, and overhaul processes would be more efficient if the internal status of the engine would be known while still on the wing before it is disassembled. The feasibility of this approach is investigated for a pilot scaled model combustor, which provides optical access and allows the selection of “defined errors” in the combustor. It consists of an atmospheric tubular combustor with an array of eight premixed swirl burners with a maximum output of 160 kW. The operating conditions of one of the eight burners concerning power and air-fuel ratio, can be controlled. A power distribution between the burners is typical fault in an aircraft combustor and will be investigated in this study. It is observed that it is possible to determine small deviations by measuring density profiles applying a tomographic background-oriented schlieren (BOS) technique behind the combustor. Additionally, particle image velocimetry is used to measure differences in the velocity field of the exhaust gases. This study shows that a minimum power deviation of one burner in an array of a total of eight burners is detectable in the exhaust plane with the above mentioned measurement techniques.

Thermal Modeling of Concentrated Photovoltaic Thermal System at Different Operating Conditions

2018 ◽  
Author(s):  
Shah Alam ◽  
Rahul Yelamanchili
Keyword(s):  
Heat Flux ◽  
Thermal Modeling ◽  
Photovoltaic Cells ◽  
Primary Objective ◽  
Operating Conditions ◽  
Thermal System ◽  
Maximum Output ◽  
Cooling Channel ◽  
Element Analysis ◽  
Photovoltaic Thermal System

Concentrated photovoltaic thermal system is a reliable solar energy system that utilizes sunlight of higher concentration on a photovoltaic cell to generate energy that is superior to conventional solar systems due to fewer space requirements and high electrical and thermal efficiencies. The primary objective of this thesis was to test two operating conditions of the concentrated photovoltaic thermal system and find the condition that delivers maximum output when compared to the other. The first condition tested in this research included variable velocity of water flowing in the cooling channel while a constant amount of heat flux was applied on the photovoltaic cells. The second tested condition included constant velocity of water flowing in the cooling channel while varying the amount of heat flux applied on the photovoltaic cells. Through mathematical modeling, that includes, thermal modeling and energy analysis was carried out for the concentrated photovoltaic thermal system along with simulations of the system that were performed using a three-dimensional finite element analysis software called Ansys Workbench (Fluent). The results from this research provide a useful path in improving the efficiency of the concentrated photovoltaic thermal system.

Prototyping and Simulated Analysis of Autonomous Swarm-Bots

2018 ◽  
Author(s):  
Maulikkumar Dhameliya ◽  
Sidharth Sher ◽  
Souma Chowdhury
Keyword(s):  
Low Cost ◽  
Raspberry Pi ◽  
System A ◽  
Simulated Environment ◽  
3D Printed ◽  
Modular Platform ◽  
And Performance ◽  
Small Form Factor ◽  
Rate Of Success ◽  
Simulated Analysis

Teams of small (mm-to-cm scale) robots, often known as swarm-bots, can provide unique functionality owing to their small form factor, distributed sensing capabilities, resilience to disruptions and agent-loss, and likely low cost. Such swarm-bots are being increasingly touted to support various indoor surveillance, hazard detection, and search and rescue missions. This paper presents the conceptual design, fabrication, and testing of a new cm-scale wheeled swarm-bot. Simulated investigation of a simple particle-swarm-inspired approach to coordinated path planning for these swarm-bots is also presented. The swarm bot is developed around a modular platform, comprising snap-on (3D printed) structural components, a stepper-motor actuated wheel system, a Raspberry Pi computing node, a wireless radio module, a Lipo battery, and proximity sensors; all components are readily detachable, thereby allowing reconfiguration flexibility. Through three design generations, a stable prototype offering >20cm/s speed and ∼50 min endurance, was developed, assembled and tested. A virtual simulated environment is developed by combining MATLAB-based modules and a V-Rep environment, in order to simulate the coordinated operation of these swarm-bots. A 78% rate of success in completing target (light source) search missions was observed during the numerical experiments, and performance robustness was observed to improve with increasing swarm size.

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