High-Efficiency High-Temperature Radiation Heat Shields

1972 ◽  
Vol 9 (1) ◽  
pp. 23-26 ◽  
Author(s):  
C. K. Crawford
1968 ◽  
Vol 90 (4) ◽  
pp. 665-678 ◽  
Author(s):  
B. Sternlicht

The paper presents gas bearing turbomachinery developments for the past decade. With the aid of examples of eight different requirements, it answers the question: “Why Gas-Bearing Turbomachinery?” These examples cover: No Contamination, high efficiency, low temperature, high temperature, radiation damage, reliability and long life, high speed and long life, and simplification. The paper points out the parameters and design procedures that are important to gas bearing turbomachinery designers. A table which enables selection of gas bearings and one which compares rotor weights for motor and turbine drives are included. Several remaining problem areas are identified and an example of bearing distortion, resulting from friction, is given.


2018 ◽  
Author(s):  
Matthias May ◽  
Kira Rehfeld

Greenhouse gas emissions must be cut to limit global warming to 1.5-2C above preindustrial levels. Yet the rate of decarbonisation is currently too low to achieve this. Policy-relevant scenarios therefore rely on the permanent removal of CO<sub>2</sub> from the atmosphere. However, none of the envisaged technologies has demonstrated scalability to the decarbonization targets for the year 2050. In this analysis, we show that artificial photosynthesis for CO<sub>2</sub> reduction may deliver an efficient large-scale carbon sink. This technology is mainly developed towards solar fuels and its potential for negative emissions has been largely overlooked. With high efficiency and low sensitivity to high temperature and illumination conditions, it could, if developed towards a mature technology, present a viable approach to fill the gap in the negative emissions budget.<br>


2018 ◽  
Author(s):  
Matthias May ◽  
Kira Rehfeld

Greenhouse gas emissions must be cut to limit global warming to 1.5-2C above preindustrial levels. Yet the rate of decarbonisation is currently too low to achieve this. Policy-relevant scenarios therefore rely on the permanent removal of CO<sub>2</sub> from the atmosphere. However, none of the envisaged technologies has demonstrated scalability to the decarbonization targets for the year 2050. In this analysis, we show that artificial photosynthesis for CO<sub>2</sub> reduction may deliver an efficient large-scale carbon sink. This technology is mainly developed towards solar fuels and its potential for negative emissions has been largely overlooked. With high efficiency and low sensitivity to high temperature and illumination conditions, it could, if developed towards a mature technology, present a viable approach to fill the gap in the negative emissions budget.<br>


2021 ◽  
Vol 414 ◽  
pp. 128760
Author(s):  
Wen-Bo Li ◽  
Di Zhou ◽  
Wen-Feng Liu ◽  
Jin-Zhan Su ◽  
Fayaz Hussain ◽  
...  

Author(s):  
Hassan Qandil ◽  
Weihuan Zhao

A novel non-imaging Fresnel-lens-based solar concentrator-receiver system has been investigated to achieve high-efficiency photon and heat outputs with minimized effect of chromatic aberrations. Two types of non-imaging Fresnel lenses, a spot-flat lens and a dome-shaped lens, are designed through a statistical algorithm incorporated in MATLAB. The algorithm optimizes the lens design via a statistical ray-tracing methodology of the incident light, considering the chromatic aberration of solar spectrum, the lens-receiver spacing and aperture sizes, and the optimum number of prism grooves. An equal-groove-width of the Poly-methyl-methacrylate (PMMA) prisms is adopted in the model. The main target is to maximize ray intensity on the receiver’s aperture, and therefore, achieve the highest possible heat flux and output concentration temperature. The algorithm outputs prism and system geometries of the Fresnel-lens concentrator. The lenses coupled with solar receivers are simulated by COMSOL Multiphysics. It combines both optical and thermal analyses for the lens and receiver to study the optimum lens structure for high solar flux output. The optimized solar concentrator-receiver system can be applied to various devices which require high temperature inputs, such as concentrated photovoltaics (CPV), high-temperature stirling engine, etc.


2021 ◽  
Vol 485 ◽  
pp. 126730
Author(s):  
Shun Cao ◽  
Yi Jin ◽  
Hongguang Dong ◽  
Tingbiao Guo ◽  
Zhenchao Liu ◽  
...  

Author(s):  
Ihor S. Diakunchak ◽  
Greg R. Gaul ◽  
Gerry McQuiggan ◽  
Leslie R. Southall

This paper summarises achievements in the Siemens Westinghouse Advanced Turbine Systems (ATS) Program. The ATS Program, co-funded by the U.S. Department of Energy, Office of Fossil Energy, was a very successful multi-year (from 1992 to 2001) collaborative effort between government, industry and participating universities. The program goals were to develop technologies necessary for achieving significant gains in natural gas-fired power generation plant efficiency, a reduction in emissions, and a decrease in cost of electricity, while maintaining current state-of-the-art electricity generation systems’ reliability, availability, and maintainability levels. Siemens Westinghouse technology development concentrated on the following areas: aerodynamic design, combustion, heat transfer/cooling design, engine mechanical design, advanced alloys, advanced coating systems, and single crystal (SC) alloy casting development. Success was achieved in designing and full scale verification testing of a high pressure high efficiency compressor, airfoil clocking concept verification on a two stage turbine rig test, high temperature bond coat/TBC system development, and demonstrating feasibility of large SC turbine airfoil castings. The ATS program included successful completion of W501G engine development testing. This engine is the first step in the W501ATS engine introduction and incorporates many ATS technologies, such as closed-loop steam cooling, advanced compressor design, advanced sealing and high temperature materials and coatings.


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