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有机工质余热发电技术的研究进展及其应用前景 总被引：1，自引：0，他引：1
工业余热、太阳能热、地热、生物质能、海洋温差等都是低品位热源,有机朗肯循环(ORC)可以有效提高低品位热源的利用效率。提高ORC效率的关键是根据应用对象的特点选择合适的有机工质,国内外学者对各种领域内应用的ORC工质进行了大量深入的工作,并且取得很多成果,我国低温余热资源十分丰富,而能源利用率却不高,采用ORC提高能源回收以及利用率,在我国各行各业在都有着广阔的应用前景。 相似文献
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The scope of the introduced study focuses on the analysis of heat as well as flow transportation in an oblique Casson nanofluid in the presence of an aligned magnetic field. The fluid is supposed to impinge obliquely on a sheet that stretches in both directions of the x‐axis with heat generation. The moulded partial differential equations computed numerically with the shooting procedure by adopting the Runge Kutta Fehlberg method. The change in the behaviour of the emerging fluid parameters are described graphically and their results are shows in tables. The outcomes disclosed that the fluid velocity declined for Casson fluid parameter and the aligned angle of the magnetic field. In addition, with the increase in the Casson fluid parameter and aligned angle of magnetic field, the fluid temperature and concentration rise. The outcomes of this study may be beneficial to control the rate of heat and mass transportation as well as controlling fluid velocity in industry to obtain a final product of the desired quality. 相似文献
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This paper deals with the effect of magnetic fields (Br, Bθ, Bz) applied in r-, θ-, z-directions, respectively, on entropy production and heat transfer and in a horizontal cylinder filled with an Al2O3-water nanofluid. The results are verified using literature data. For different Richardson, Ri, and Hartmann numbers, Ha, the nanoparticles (NP) ϕ, and magnetic field orientation combined effect provide a better understanding of heat transfer and entropy optimization. The results indicate that entropy production and heat transfer and rates depend on magnetic field intensity and direction. Also, increasing Ri and NP increases entropy generation and heat transfer. Finally, applying a radial magnetic field promotes a better convective heat transfer and minimizes entropy production. 相似文献
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浅析玻璃行业余热利用与发电 总被引：5，自引：0，他引：5
本文式图通过对玻璃熔窑排出的高温烟气余热运用的现状,剖析玻璃工厂对余热利用的不尽合理之处,进而说明在玻璃工厂进行余热发电的可能性,为玻璃厂改造和新建时对余热利用提供另一条出路。 相似文献
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Effects of Nanofluid on Peristaltic Flow of a Carreau Fluid Model in an Inclined Magnetic Field 
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下载免费PDF全文 Safia Akram 《亚洲传热研究》2014,43(4):368-383
In the present article we talk about the influence of a nanofluid on the peristaltic flow of a Carreau fluid model in the presence of an inclined channel and magnetic field. The mathematical modeling of the proposed problem is given for the two‐ dimensional and directional flow. The governing highly nonlinear coupled equations are simplified by means of the assumptions of long wavelength and low Reynolds number approximation. The solutions of the simplified coupled nonlinear equations are calculated using an analytical approach. At the end, graphical results are displayed to show the effects of various emerging parameters of interest. © 2013 Wiley Periodicals, Inc. Heat Trans Asian Res, 43(4): 368–383, 2014; Published online 3 October 2013 in Wiley Online Library ( wileyonlinelibrary.com/journal/htj ). DOI 10.1002/htj.21082 相似文献
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Power generation is one of the major industries or businesses globally. Although, at present, a major attention has been paid towards the sustainable energy technologies, both gas and steam turbines are still heavily used in the power generation sector worldwide. Usually, gas turbines are used to drive an electrical power generator in simple systems, or they are used in combined cycle plants together with steam turbines. This paper presents a comprehensive review on modelling of heat transfer and fluid flow in hot section of gas turbines used in the power generation sector. Visibly, heat transfer and fluid flow characteristics directly affect the thermal efficiency and the overall performance of the gas turbines. Hence, existing models relating to heat transfer and fluid flow inside gas turbines are discussed in detail. Primarily, methods relating to the first principle modelling, empirical modelling, and finite element modelling are reviewed comprehensively, and then, a discussion is provided together with a comparison among models in terms of their advantages and disadvantages. Moreover, some existing issues such as the environmental impact are discussed which still remain as challenges to the power generation industry together with some of the possible future directions for improvements. 相似文献
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结合炼钢电炉饱和蒸汽余热发电的工程实例,介绍炼钢电炉的余热统计情况和余热发电系统的技术方案。余热发电技术在炼钢电炉的成功应用,开辟了电炉节能减排的新途径,取得了显著的经济效益和社会效益。 相似文献
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The present work explores the consequence of the flow of micropolar fluid in an inclined microchannel when exposed to linear radiation in presence of a magnetic field. The microchannel is embedded with a porous medium and the Darcy–Forchheimer model is implemented. The walls of the microchannel facilitate the simultaneous suction and injection of the micropolar fluid. A multiple slip regime and temperature jump conditions were assumed at the boundaries. The equations are modeled and nondimensionalized using nondimensional entities and further solved with the aid of the Runge–Kutta–Fehlberg method. Entropy generated in the medium and ratio of irreversibilities is also computed. Results so obtained deliberate that enhancement in Darcy number has caused an increment in entropy generation rate whereas the opposite nature is attained for the Bejan number. Magnifying the radiation parameter has resulted in diminishing the profile of entropy generation rate and Bejan number. 相似文献
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Specific heat and thermal conductivity are important thermal properties of high-temperature heat transfer fluids and thermal storage materials for supercritical solar power plants. In the present work, nanofluids composed of ternary carbonate Li2CO3-K2CO3-Na2CO3 (4:4:2, mass ratio) and 1.0 wt.% carbon nanotubes (CNT) were prepared to obtain high-temperature heat transfer and storage media with enhanced specific heat and thermal conductivity. The dispersion of CNTs in the nanofluids was tuned by changing the evaporation temperature (100, 140, 180 and 220 °C) and adding surfactants such as sodium dodecyl benzene sulfonate (SDBS), sodium dodecyl sulfate (SDS), or gum Arabic (GA). The results showed that GA and SDS facilitate good dispersion of CNT in nanofluids at the evaporation temperatures of 140 °C and 180 °C, resulting in the formation of more needle-like nanostructures. The higher increase in the specific heat and thermal conductivity of the nanofluids with SDS at 500 °C was 78.3% and 149.2%, respectively. Additionally, the specific heat of as-prepared ternary carbonate nanofluids exhibits a good thermal stability after 30 cycles of thermal shock experiments. 相似文献
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为了回收轧钢生产线加热炉冷却水汽化余热,提出了一种新型蒸汽-低沸点介质联合双循环余热发电装置。以某轧钢厂10t／h余热蒸汽为例,阐述了该装置的构成与热力循环过程,对该装置进行了设计计算,结果表明在设计工况下发电效率理论上可以达到5．4％,年净产电量为263万kWh。对实际运行下可能出现的变工况运行进行了分析,定性地讨论了余热蒸汽的干度、压力和流量对发电量和发电效率带来的影响。最后对利用该装置进行余热发电的节能与环保效益进行了分析,分析结果表明该装置的静态投资回收期仅为1．8年,年节约标准煤972．8t,年减排二氧化碳330t,社会效益明显。 相似文献
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Cooling of a bluff body is a topic of interest for many engineers and scientists. Forced convection over the bluff body generates flow separation, which in turn affects the heat transfer characteristics and increases the irreversibilities involved in the system. In the present study, flow over a rectangular solid body with constant heat flux is considered. The governing flow and energy equations are solved in two‐dimensional space numerically using a control volume approach. In order to investigate the effect of the fluid properties on the heating process, three different fluids are taken into account. These are air, ethylene glycol and therminol. To determine the irreversibilities involved in the system, entropy analysis is carried out. It is found that fluid properties have considerable effect on the entropy generation. The entropy generation due to heat transfer well exceeds the entropy generation due to fluid friction. The surface temperature of the solid body highly depends on the cooling fluid employed. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
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Onder Kizilkan 《国际能源研究杂志》2020,44(15):12329-12343
The main objective of this study is to investigate the feasibility of a waste heat recovery (WHR) closed Brayton cycle (BC) working with supercritical carbon dioxide (sCO2). For this aim, an actual WHR steam Rankine cycle (RC) in a cement plant was evaluated thermodynamically. After, a sCO2-BC was theoretically adapted to the actual WHR system for the performance assessment. Both systems were analyzed comparatively in terms of energy and exergy. According to the results, the sCO2-BC showed higher performance than the actual steam RC with a net electricity generation of 9363 kW where it was calculated as 8275 kW for the actual cycle. In addition, the energy efficiencies were found to be 27.6% and 24.18% where the exergy efficiencies were calculated as 58.22% and 51.39% for sCO2-BC and steam RC, respectively. In the following part of the study, the closed BC was examined for different supercritical working fluids, namely, CO2, pentafluoroethane (R125), fluoromethane (R41), and sulfur hexafluoride (SF6). Parametrical analyses were conducted to determine the effects of the system parameters such as turbine inlet temperature, compressor inlet temperature, and pressure ratio on the cycle performance. The simulation results of the comparative study showed that, among the supercritical fluids, the CO2 demonstrated a higher performance for the closed BC with an energy efficiency of 27.9% followed by R41, SF6, and R125. As a result, the utilization of sCO2-BC for WHR can be sustainably adapted and extended for environmentally friendly energy generation. 相似文献