Design and Analysis of Hot Internals for the Reactivity Control and Reserve Shutdown Units Under Test at the Helium Test Facility

2008 ◽  
Author(s):  
E. J. J. Beyer ◽  
K. J. Craig
Keyword(s):  
South Africa ◽  
Thermal Insulation ◽  
Elevated Temperatures ◽  
Thermal Protection ◽  
Thermal Analyses ◽  
Thermal Design ◽  
Test Facility ◽  
Maximum Pressure ◽  
Operating Pressure ◽  
Worst Case

This paper describes the design process followed by Westinghouse Electric South Africa for the insertion of hot internals into the Reactivity Control System (RCS) and Reserve Shutdown System (RSS) Units Under Test (UUTs) at the Helium Test Facility (HTF) at Pelindaba, South Africa. The aim of the UUTs is to allow the validation of the high temperature operation of the RCS and RSS systems for implementation into the proposed Demonstration Power Plant of the PBMR. The units use electrical heaters to obtain pebble-bed reactor thermal conditions for both the control rods and small absorber spheres (SAS) under a pressurized helium environment. Design challenges include providing for strength under elevated temperatures (900°C maximum); pressure boundary integrity (9MPa maximum); separation of different volumes (representing core barrel, reactor citadel and other Reactor Pressure Vessel (RPV) volumes); thermal protection of carbon steel vessels by using thermal insulation; allowing for diverse thermal expansion coefficients of different materials; allowing for depressurization events within the insulation and internals; having access for temperature, pressure, stress and proximity sensors and electrical wiring through high pressure penetrations; and provision for assembly of the hot internals both on and off-site. Several thermal analyses using Computational Fluid Dynamics (CFD) were performed to evaluate both worst-case and operational conditions of the UUTs. Factors that were considered include thermal insulation properties, heat transfer modes (internal radiation, external radiation and natural convection, forced internal convection for cooling) and operating pressure (ranging from 1 to 9MPa). The thermal design uses elements originally proposed for hot gas duct design. The results obtained show that the proposed design satisfies ASME VIII requirements of the pressure boundary and that all challenges are successfully met.

Implementing energy efficiency policy in housing in South Africa

2005 ◽  
Vol 16 (3) ◽  
pp. 38-44 ◽  
Author(s):  
HC Harris ◽  
DLW Krueger
Keyword(s):  
South Africa ◽  
Energy Efficiency ◽  
South African ◽  
Thermal Insulation ◽  
Thermal Design ◽  
Energy Efficiency Policy ◽  
Naturally Ventilated Buildings ◽  
Objective Basis ◽  
Research Document

The Thermal Insulation Association of South Africa (TIASA) is supporting government measures to promote energy efficiency in South African buildings. The research document titled: ‘New standards of thermal design to provide comfort and energy efficiency in South African housing’, has been adopted by TIASA, and details an objective basis for a standard. The S.A.N.S. 283 titled: ‘Energy efficiency for naturally ventilated buildings’ has as its premise, the same assumptions and methodologies as the research document. The provision of comfort in all housing in South Africa, including the problematic 30/36 m2 subsidy house – can be a reality with the proposals.

scholarly journals Computational Prediction of Susceptibility to Biofilms Growth: Two-Dimensional Analysis of Critical Construction Details

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 293
Author(s):  
Václav Kočí ◽  
Jan Kočí ◽  
Jiří Maděra ◽  
Jaroslav Žák ◽  
Robert Černý
Keyword(s):  
Thermal Insulation ◽  
Thermal Protection ◽  
Computational Prediction ◽  
Vapor Condensation ◽  
Two Dimensional ◽  
Case Scenario ◽  
Protection Measure ◽  
Worst Case ◽  
Exterior Surface ◽  
Insulation Systems

Retrofitting of historical and traditional buildings is an effective thermal protection measure. The presence of thermal insulation in the composition of building envelopes might, however, bring some shortages due to a decrease of exterior surface temperatures or possible water vapor condensation. These shortages can improve living conditions for various microorganisms on the exterior surfaces, especially in the case of interior thermal insulation systems that are typical with thermal bridges and thus supply the surface with heat to a greater extent. This paper, therefore, aims at the investigation of hygrothermal conditions in selected critical construction details and evaluates the results from the point of view of potential biofilms growth. Two-dimensional modeling of coupled heat and moisture is applied and the hygrothermal patterns are evaluated based on an adjusted isopleth growth model. The results showed that the duration of favorable conditions for biofilms growth is relatively low, accounting for less than 180 h in the worst-case scenario. It means the exterior surfaces of historical buildings provided with interior thermal insulation systems are not threatened by biofilms growth. Anyway, other negative aspects have been revealed that should be treated individually. Possible wood decay or increased hygrothermal straining are the typical examples in that respect.

scholarly journals Novel Structure and Thermal Design and Analysis for CubeSats in Formation Flying

Aerospace ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 150
Author(s):  
Yeon-Kyu Park ◽  
Geuk-Nam Kim ◽  
Sang-Young Park
Keyword(s):  
Analytical Model ◽  
Formation Flying ◽  
Thermal Environment ◽  
Thermal Analyses ◽  
Thermal Design ◽  
Analytical Models ◽  
Test Results ◽  
Solar Panels ◽  
Novel Structure ◽  
Micro Propulsion

The CANYVAL-C (CubeSat Astronomy by NASA and Yonsei using a virtual telescope alignment for coronagraph) is a space science demonstration mission that involves taking several images of the solar corona with two CubeSats—1U CubeSat (Timon) and 2U CubeSat (Pumbaa)—in formation flying. In this study, we developed and evaluated structural and thermal designs of the CubeSats Timon and Pumbaa through finite element analyses, considering the nonlinearity effects of the nylon wire of the deployable solar panels installed in Pumbaa. On-orbit thermal analyses were performed with an accurate analytical model for a visible camera on Timon and a micro propulsion system on Pumbaa, which has a narrow operating temperature range. Finally, the analytical models were correlated for enhancing the reliability of the numerical analysis. The test results indicated that the CubeSats are structurally safe with respect to the launch environment and can activate each component under the space thermal environment. The natural frequency of the nylon wire for the deployable solar panels was found to increase significantly as the wire was tightened strongly. The conditions of the thermal vacuum and cycling testing were implemented in the thermal analytical model, which reduced the differences between the analysis and testing.

Thermal Analysis of Cooling System in a Gas Turbine Transition Piece

2011 ◽  
Author(s):  
Jun Su Park ◽  
Namgeon Yun ◽  
Hokyu Moon ◽  
Kyung Min Kim ◽  
Sin-Ho Kang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Thermal Stresses ◽  
Cooling System ◽  
Structural Information ◽  
Thermal Analyses ◽  
Thermal Design ◽  
Transfer Coefficients ◽  
Transition Piece ◽  
Inlet Conditions

This paper presents thermal analyses of the cooling system of a transition piece, which is one of the primary hot components in a gas turbine engine. The thermal analyses include heat transfer distributions induced by heat and fluid flow, temperature, and thermal stresses. The purpose of this study is to provide basic thermal and structural information on transition piece, to facilitate their maintenance and repair. The study is carried out primarily by numerical methods, using the commercial software, Fluent and ANSYS. First, the combustion field in a combustion liner with nine fuel nozzles is analyzed to determine the inlet conditions of a transition piece. Using the results of this analysis, pressure distributions inside a transition piece are calculated. The outside of the transition piece in a dump diffuser system is also analyzed. Information on the pressure differences is then used to obtain data on cooling channel flow (one of the methods for cooling a transition piece). The cooling channels have exit holes that function as film-cooling holes. Thermal and flow analyses are carried out on the inside of a film-cooled transition piece. The results are used to investigate the adjacent temperatures and wall heat transfer coefficients inside the transition piece. Overall temperature and thermal stress distributions of the transition piece are obtained. These results will provide a direction to improve thermal design of transition piece.

ZIRCONIA FIBERS AS A COMPONENT OF HIGH TEMPERATURE THERMAL INSULATION (review)

2021 ◽  
pp. 79-86
Author(s):  
V.G. Babashov ◽  
◽  
N.M. Varrik ◽  
Keyword(s):  
High Temperature ◽  
Thermal Insulation ◽  
Zirconium Oxide ◽  
Thermal Protection ◽  
Sol Gel ◽  
Precursor Solution ◽  
Technical Literature ◽  
Thermal Protection Systems ◽  
Insulation Materials ◽  
Protection Systems

Based on the analysis of recent publications of scientific and technical literature, data on the production of zirconium oxide fibers used for the manufacture of high-temperature thermal insulation materials are presented. Information is provided on various methods of obtaining zirconium oxide fibers (methods of impregnation of the template and molding of the mixture, sol-gel method of spinning a fiber-forming precursor solution), as well as on the technique of fiber molding (manual pulling, dry and wet spinning, blowing and electrospinning). The use of such fibers for the production of thermal insulation materials (felts, cords and blocks) instead of currently existing materials made of aluminum oxide-based fibers can significantly increase the operating temperatures of the thermal protection systems.

Shale gas leakage in lower Ecca shales during contact metamorphism by dolerite sill intrusions in the Karoo Basin, South Africa

2021 ◽  
Author(s):  
V. Nengovhela ◽  
B. Linol ◽  
L. Bezuidenhout ◽  
T. Dhansay ◽  
T Muedi ◽  
...  
Keyword(s):  
South Africa ◽  
Grain Boundaries ◽  
Shale Gas ◽  
Elevated Temperatures ◽  
Contact Metamorphism ◽  
Microscopy Imaging ◽  
Gas Leakage ◽  
Karoo Basin ◽  
Maximum Temperatures ◽  
Host Rocks

Abstract Contact metamorphism along widespread dolerite sills and dykes, emplaced at 182 to 183 Ma through the sedimentary host rocks of the Karoo Basin, triggered devolatilization of carbon-rich shales of the Lower Ecca Group. Hornfel samples collected from drill cores that intersect dolerite sills were analyzed for mineral phase equilibria, chemistry and porosity to characterize thermal aureoles at various distances from sill intrusions. Andalusite-chiastolite and cordierite porphyroblasts with biotite and muscovite occur within 10 to 20 m of many intrusive contacts. These metamorphic minerals crystallized when host shales attained maximum temperatures ranging between 450 and 600°C. Scanning electron microscopy imaging confirms that the hornfels are compact and that their metamorphic minerals limit porosity along grain boundaries. In few cases intra-mineral porosity occurs within individual crystals such as calcite, andalusite and cordierite. Disequilibrium metamorphic textures such as irregular grain boundaries, and inclusions in andalusite and cordierite reveal that the elevated temperatures were too short-lived to accomplish complete (re)crystallization. Thermal modeling results are consistent with the observed metamorphic mineral assemblages. Gas leakage calculations along a 7 m and a 47 m thick dolerite sill that intrude toward the top of the Whitehill Formation suggest that methane volumes ranging between 8 to 15 Tcf were generated during the sill emplacement. Methane was likely released into the atmosphere through hydrothermal vent complexes that are well preserved in the western Karoo Basin. If such loss was widespread across the entire basin, the implications for paleo-climate change and preserved shale gas reserves in the Karoo Basin of South Africa would be significant.

scholarly journals Aero-Thermal Design and Testing of Advanced Turbine Blades

1997 ◽  
Author(s):  
M. Haendler ◽  
D. Raake ◽  
M. Scheurlen
Keyword(s):  
Gas Turbines ◽  
Full Range ◽  
Turbine Blades ◽  
Design Procedure ◽  
Thermal Design ◽  
Test Facility ◽  
Optical Pyrometer ◽  
Electrical Systems ◽  
Operation Conditions ◽  
Improved Performance

Based on the experience gained with more than 80 machines operating worldwide in 50 and 60 Hz electrical systems respectively, Siemens has developed a new generation of advanced gas turbines which yield substantially improved performance at a higher output level. This “3A-Series” comprises three gas turbine models ranging from 70 MW to 240 MW for 50 Hz and 60 Hz power generation applications. The first of the new advanced gas turbines with 170 MW and 3600 rpm was tested in the Berlin factory test facility under the full range of operation conditions. It was equipped with various measurement systems to monitor pressures, gas and metal temperatures, clearances, strains, vibrations and exhaust emissions. This paper presents the aero-thermal design procedure of the highly thermal loaded film cooled first stage blading. The predictions are compared with the extensive optical pyrometer measurements taken at the Siemens test facility on the V84.3A machine under full load conditions. The pyrometer was inserted at several locations in the turbine and radially moved giving a complete surface temperature information of the first stage vanes and blades.

scholarly journals Recent advancements in shape optimization of aero spiked high speed re-entry vehicle using CFD

2018 ◽  
Vol 172 ◽  
pp. 01007
Author(s):  
Harish Panjagala ◽  
E L N Rohit Madhukar ◽  
I Ravi Kiran
Keyword(s):  
High Speed ◽  
Structural Integrity ◽  
Elevated Temperatures ◽  
Thermal Protection ◽  
Space Vehicle ◽  
Protection Systems ◽  
Ultimate Outcome ◽  
Increasing Demand ◽  
Space Activities ◽  
Intense Heat

Due to increasing demand of High Speed Re-entry vehicles for Space activities within the world, a serious issue associated with the method of deceleration down a vehicle is by the intense heat generated because of development of stronger shocks at the nose. The price of thermal protection systems (TPS) to cut back the warmth generated by the return vehicles is extremely high. In this paper, the ultimate outcome is to cut back the aero heating which is achieved by introducing a spike at frontal region of the nose. Additionally, this spike avoids the deterioration and preserves the structural integrity of space vehicle over elevated temperatures. Further, four totally different geometries of tip specifically Blunt, Slender, Snap and Pan for the aerospike has been introduced and their impact on performance is evaluated and compared with the vehicle having TPS. Hence, usage of aerospike in return vehicles is the most successful and economical over different protection system.

Preparation and Properties of Phase Change Thermal Insulation Materials

2018 ◽  
Vol 281 ◽  
pp. 131-136
Author(s):  
Shi Chao Zhang ◽  
Wei Wu ◽  
Yu Feng Chen ◽  
Liu Shi Tao ◽  
Kai Fang ◽  
...  
Keyword(s):  
Phase Change ◽  
Thermal Insulation ◽  
Calcium Silicate ◽  
Phase Change Materials ◽  
Performance Test ◽  
Thermal Protection ◽  
Insulation Material ◽  
Insulation Materials ◽  
Short Time ◽  
Change Material

With the increase of the speed of vehicle, the thermal protection system of its powerplant requires higher insulation materials. Phase change materials can absorb large amounts of heat in short time. So the introduction of phase change materials in thermal insulation materials can achieve efficient insulation in a limited space for a short time. In this paper, a new phase change thermal insulation material was prepared by pressure molding with microporous calcium silicate as matrix and Li2CO3 as phase change material. The morphology stability, exudation and heat insulation of the materials were tested. The results show that the porous structure of microporous calcium silicate has a good encapsulation when the phase transition of Li2CO3 is changed into liquid. And the material has no leakage during use. The thermal performance test also shows that the insulation performance of the material has obvious advantages in the short term application.

South Africa at a Turning Point?

2015 ◽  
Vol 53 (3) ◽  
pp. 477-486 ◽  
Author(s):  
Elke Zuern
Keyword(s):  
South Africa ◽  
Turning Point ◽  
Case Scenario ◽  
State Collapse ◽  
Worst Case ◽  
South Africans ◽  
Nelson Mandela ◽  
Wide Range ◽  
Electricity Provision

South Africa is at a crossroads. The state has not adequately addressed dire human development needs, often failing to provide the services it constitutionally guarantees. As a result, citizens are expressing their frustrations in a variety of ways, at times including violence. These serious challenges are most readily apparent in poverty, inequality and unemployment statistics, but also in electricity provision, billing and affordability as well as a recent spate of racially motivated attacks which highlight the tension both among South Africans and between South Africans and darker skinned foreigners. The country has, however, been on the brink before and avoided the worst-case scenario of full-scale civil war and state collapse. Far too often South Africa's past successes have been attributed to the role of one man, Nelson Mandela. While Mandela was indeed an extraordinary human being who rightly deserved the international awards and accolades as well as the deep admiration of so many, South Africa's triumphs as a society and a state are the product of both cooperative and conflicting contributions by a wide range of actors. A central question at the present juncture is how well equipped domestic actors and institutions are to address the crisis. The following pages seek to provide some insights and through the perspectives of three authors to consider causes and possible responses.

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