共查询到19条相似文献,搜索用时 171 毫秒
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回热器是10MW高温气冷堆氦气透平直接循环(HTR-10GT)发电的重要设备之一,它的主要功能是为了利用透平出口的高温氦气加热反应堆入口氦气温度,以保证反应堆入口的氦气温度满足设计值,提高氦气透平能量转换装置的效率,并保证系统在满功率以及启动和停堆的各种工况下稳定运行。本文介绍了回热器的主要参数、结构特点、热工水力分析以及强度分析。 相似文献
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采用更加真实的阻力模型分析了流动阻力对10MW高温气冷堆(HTR-10)氦气透平循环特性的影响规律。分析结果表明,高温气冷堆氦气透平循环的压力损失主要由局部阻力和摩擦阻力组成。10MW高温气冷堆闭式氦气透平循环(HTR-10GT)发电系统在实际充装量调节及额定工况下,氦气在部件连接管道的局部压降占82.4%,沿程阻力压降占17.6%。氦气充装量减小时,局部压损系数不变而沿程阻力系数增大,导致循环效率降低;当充装量由100%降低到30%,连接管道的局部压降份额下降约20%,系统效率下降15%左右。随着充装量的减小,做功部件的进出口压力随充装量的变化线性变化,压气机的压比略有增大,透平的膨胀比有较大幅度的非线性增大。 相似文献
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CO2是零ODP、低GWP的天然制冷剂,在冷库制冷系统中应用前景广阔。本文针对用于低温冷库的两级节流中间完全冷却CO2跨临界双级压缩制冷循环(DTCC循环)建立数学模型,通过计算不同工况,分析蒸发温度、压缩机等熵效率、气冷器出口温度、排气压力以及回热循环方式对DTCC循环制冷系数的影响规律;给出DTCC循环的最优排气压力和最佳中间压力的计算式。研究表明:在蒸发温度-30~10 ℃、气冷器出口温度30~45 ℃范围内,DTCC循环的最优排气压力约比相同工况下的单级跨临界制冷循环的最优排气压力低0.3 MPa;低压级排气采用预冷气冷器、在高压级气冷器出口设置回热器均可有效改善DTCC循环的制冷系数。 相似文献
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讨论了运动回热器的泵热制冷作用,建立了运动回热器控制方程的解析解。根据由热声理论得到的回热器泵热作用判据,指出回热器的泵热制冷作用有流道上有截面分布,这个截在分布受回热器运动的严重影响;讨论了回热器运动的相位及振幅对其泵热制冷作用的影响,所得结论表明了热声理论对热式热机工程实践发展的重要指导意义。 相似文献
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高温气冷堆氦气透平循环热工特性的初步研究 总被引:13,自引:1,他引:12
模块式高温气冷堆氦气透平直接循环发电方案是建立在带有回热器、预冷器、间冷器的闭式布雷登循环的理论基础上,是集安全性、经济性为一体的先进方案,有着良好的发展前景。本文对高温堆氦气透平循环的热力过程进行了分析,揭示了各参九之间的关系。然后,对高温堆氦气透平循环进行了优化计算,得到了一个优化设计方案。另外,还对高温堆氦所透平循环的功率控制特性进行了简要分析。本文的研究结果显示高温堆氦气透平循环效率可达47.9%,将来随着材料科学和相关技术的发展循环效率有望进一步提高。 相似文献
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The thermodynamic optimization of differing Reverse Brayton Refrigeration (RBR) cycle configurations is presented in this study. These cycle configurations include: Conventional 1-stage compression cycle; Conventional 2-stage compression cycle; 1-stage compression Modified cycle with intermediate cooling of the recuperator using an auxiliary cooler; and an Integrated 2-stage expansion RBR cycle. For high pressure ratio applications, multi-stage compressors with intercooling are considered. Analytical solutions for the conventional cycles are developed including thermal and fluid flow irreversibilities of the recuperators and all heat exchangers in addition to the compression and expansion processes. Exergy analysis is performed and the exergy destruction of different components of the RBR cycles for different configurations is presented and the effects of important system parameters on performance are investigated. Thermodynamic optimization of the cycles with intermediate cooling of the recuperator is included. Effects of the 2nd law/exergy efficiency of the auxiliary cooler on the total system efficiencies are presented. 相似文献
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The possibility to estimate the efficiency of recuperative heat exchangers is shown. The estimation takes into account the effect of gas dynamic energy separation using the known parameters: the efficiency of the recuperator, the number of transfer units, and the specific surface area expressed through recovery temperatures. The dependences of the recuperator parameters on the reduced rates of heat-transfer agents are calculated at Prandtl numbers considerably different from unity. 相似文献
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Performance comparison of single-stage mixed-refrigerant Joule–Thomson refrigeration cycle (MJTR) and pure-gas reverse Brayton cycle (RBC) at fixed-temperatures from 80 to 180 K was made in this paper. The simulation was mainly conducted under nonideal conditions with extrinsic irreversibilities. Exergy efficiency and volumetric cooling capacity are two main evaluation parameters. Exergy loss distributions along the cycles were analyzed. Under ideal conditions, RBC achieved the highest exergy efficiency at all temperatures, but lower volumetric cooling capacity than MJTR at middle-high temperatures. Under nonideal conditions, both the exergy efficiency and volumetric cooling capacity of MJTR were obviously superior to RBC from 100 to 180 K, but inferior to RBC at 80 K. Two reasons account for the sharp performance degradation of MJTR: The high fraction of neon resulted in large entropy generation and exergy loss in throttling process. Larger recuperator duty and WLMTD lead to larger losses in the recuperator. 相似文献
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A high temperature superconductivity cable must be cooled below the nitrogen liquefaction temperature to apply the cable to power generation and transmission systems under superconducting state. To maintain the superconducting state, a reliable cryocooler system is also required. The design and fabrication of a cryocooler system have been performed with a reverse Brayton cycle using neon gas as a refrigerant. The system consists of a compressor, a recuperator, a cold-box, and control valves. The design of the system is made to have 1 kW cooling capacity. The heat loss through multilayer insulators is calculated. Conduction heat loss is about 7 W through valves and access ports and radiation heat loss is about 18 W on the surface of a cryocooler. The design factors are discussed in detail. 相似文献
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以热效率为目标,应用有限时间热力学的方法优化了恒温热源务件下内可逆闭式中冷回热布雷顿循环的中间压比分配和高低温侧换热器、中冷器及回热器热导率分配.得到循环最大热效率.进一步对总压比优化,可以得到双重最大效率.通过数值计算,研究了一些重要参数对循环优化结果的影响. 相似文献
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This study explores the use of teaching-learning-based optimization (TLBO) and artificial bee colony (ABC) algorithms for determining the optimum operating conditions of combined Brayton and inverse Brayton cycles. Maximization of thermal efficiency and specific work of the system are considered as the objective functions and are treated simultaneously for multi-objective optimization. Upper cycle pressure ratio and bottom cycle expansion pressure of the system are considered as design variables for the multi-objective optimization. An application example is presented to demonstrate the effectiveness and accuracy of the proposed algorithms. The results of optimization using the proposed algorithms are validated by comparing with those obtained by using the genetic algorithm (GA) and particle swarm optimization (PSO) on the same example. Improvement in the results is obtained by the proposed algorithms. The results of effect of variation of the algorithm parameters on the convergence and fitness values of the objective functions are reported. 相似文献
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为了研究板翅式换热器在沸腾相变换热情况下的传热及压降特性,设计一套采用氟里昂蒸气压缩循环的液体冷却试验系统,其中板翅式换热器作为蒸发器,R22作为制冷剂,热水作为被冷却液体提供制冷剂蒸发所需热量。对该系统的运行工况、参数范围及系统各部件(包括压缩机、冷凝器、毛细管、板翅式蒸发器)进行设计及选择,并介绍所搭建的试验台。 相似文献
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基于前人所建立的变温热源内可逆简单等温加热修正的闭式布雷顿循环(modified closed Brayton cycle,MCBC)模型,分析了压气机压比等参数对循环性能的影响。分别以无因次功率和无因次生态学函数为优化目标,以压比和各个换热器的热导率分配为优化变量,对变温热源内可逆简单MCBC进行单目标优化。最后基于NSGA-Ⅱ算法,以无因次功率、热效率和无因次生态学函数为优化目标,以压比和各个换热器的热导率分配为优化变量,对变温热源内可逆简单MCBC进行多目标优化,并分析了相关参数的灵敏度。结果表明:常规燃烧室(regular combustion chamber,RCC)和收敛型燃烧室(converging combustion chamber,CCC)外侧流体的入口温比对单目标优化结果的影响存在着明显的相互关系;与单目标优化得到的结果相比,多目标优化得到的最优解对应的偏差指数更小,其中通过香农熵决策得到的偏差指数最小;优化变量变化±10%对最优无因次功率、最优热效率、最优无因次生态学函数及其对应的等温压降比的影响很小,其变化范围均不超过5%。 相似文献
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《低温学》2017
There are several ways to organize the flow scheme of the helium liquefiers, such as arranging the expanders in parallel (reverse Brayton stage) or in series (modified Brayton stages). In this paper, the inlet mass flow and temperatures of expanders in Collins cycle are optimized using genetic algorithm (GA). Results show that maximum liquefaction rate can be obtained when the system is working at the optimal parameters. However, the reliability of the system is not well due to high wheel speed of the first turbine. Study shows that the scheme in which expanders are arranged in series with heat exchangers between them has higher operation reliability but lower plant efficiency when working at the same situation. Considering both liquefaction rate and system stability, another flow scheme is put forward hoping to solve the dilemma. The three configurations are compared from different aspects, they are respectively economic cost, heat exchanger size, system reliability and exergy efficiency. In addition, the effect of heat capacity ratio on heat transfer efficiency is discussed. A conclusion of choosing liquefier configuration is given in the end, which is meaningful for the optimal design of helium liquefier. 相似文献