共查询到17条相似文献,搜索用时 93 毫秒
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环路声学共振多级行波热声发动机的机理研究 总被引:1,自引:0,他引:1
针对环路声学共振多级行波热声发动机的工作机理进行了研究,重点分析了环路声学共振4级行波热声发动机无负载工作情况,并比较了环路声学共振4级、8级、16级行波热声发动机的工作性能。计算结果表明,这一行波热声发动机具有较好的声场分布并通过增大回热器横截面积有效降低了回热器内的粘性流动损失。增加环路声学共振多级行波热声发动机的级数仍能获得较为理想的工作性能,并能够增加整机产生净声功率,降低谐振管消耗声功率的比例,相对传统带驻波谐振管的行波热声发动机更为紧凑。 相似文献
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对一种新型热声制冷系统—双作用行波热声制冷机进行了研究,设计了一台在气液双作用行波热声发动机上使用的行波制冷机,并通过数值模拟优化了制冷机的结构尺寸。在环境温度300K,制冷温度250K的条件下,新型的双作用制冷机的COP达到了2.74,相对卡诺效率接近60%,声功消耗为534W,制冷量为1464.9W。通过对传统的斯特林制冷机及不同结构的行波制冷机计算比较。结果表明:从压比、效率、制冷量等多角度考察,新型的双作用行波制冷机更适合与气液双作用行波热声发动机耦合工作。它具有潜在的高效率、热驱动及无运动部件的优点,非常有潜力成为常规制冷方式的一种替代技术。 相似文献
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对一种新型热声制冷系统—双作用行波热声制冷机进行了研究,设计了一台在气液双作用行波热声发动机上使用的行波制冷机,并通过数值模拟优化了制冷机的结构尺寸.在环境温度300K,制冷温度250K的条件下,新型的双作用制冷机的COP达到了2.74,相对卡诺效率接近60%,声功消耗为534W,制冷量为1464.9W.通过对传统的斯特林制冷机及不同结构的行波制冷机计算比较.结果表明:从压比、效率、制冷量等多角度考察,新型的双作用行波制冷机更适合与气液双作用行波热声发动机耦合工作.它具有潜在的高效率、热驱动及无运动部件的优点,非常有潜力成为常规制冷方式的一种替代技术. 相似文献
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针对气-液双作用行波热声发动机结构参数不一致性对系统热声转换特性的影响进行了数值模拟分析,分别讨论了回热器长度、液体活塞摩擦阻力以及液体活塞质量不对称的情况下,系统热声转换特性的变化。计算结果表明,仅改变一个基本单元的一个特定的结构参数时,整个气-液双作用行波热声发动机性能参数均发生改变,并且表现出不对称性。系统结构参数的不一致性对体积流率、压力振幅、相位以及气体温度的沿程分布均有明显影响。回热器产生的净声功率受结构参数不对称性影响显著,甚至可能出现某一基本单元回热器不产生声功率或消耗声功率的情况,值得重点关注。 相似文献
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《低温学》2015
A 300 Hz pulse tube cryocooler (PTC) driven by a three-stage traveling-wave thermoacoustic heat engine (TSTHE) has been proposed and studied in this paper. In the configuration, three identical thermoacoustic heat engine units are evenly incorporated in a closed traveling-wave loop, in which three pulse tube cryocoolers are connected to the branch of each thermoacoustic heat engine. Compared with the conventional thermoacoustic heat engine which involves a traveling-wave loop and a long resonator, it has advantages of compact size and potentially high thermal efficiency. A TSTHE–PTC system was designed, optimized and studied in detail based on the thermoacoustic theory. Firstly, numerical simulation was conducted to design the system thus the optimum structure parameters of the system were obtained. With the operating condition of 4 MPa mean pressure and high working frequency, a cooling power of 7.75 W at 77 K and an overall relative Carnot efficiency of 11.78% were achieved. In order to better understand the energy conversion characteristics of the system, distributions of key parameters such as acoustic work, phase difference, dynamic pressure, volume flow rate and exergy loss were presented and discussed. Then, the coupling mechanism of the system was investigated. In addition, influence of coupling position on the system performance was further studied. 相似文献
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在环境温度低于0℃时,常规空气源热泵会出现压比过高、效率和制冷量急剧下降等问题。为了解决这些问题,提出了电驱动双作用行波热声热泵技术。通过数值计算优化了该新型热泵的结构尺寸,设计出一台电驱动低温环境下运行的双作用行波热声热泵。在环境温度253 K(-20℃),泵热温度323 K(50℃)的条件下,新型热泵的制热系数达到了2.93,相对卡诺效率接近64%,泵热量为4 722.6W,压比仅为1.19。热泵多种运行工况的计算结果表明该热泵能够在效率变化较小的情况下调节泵热量的大小;环境温度和泵热温度的改变对系统的运行状态影响不大;该系统制冷时亦有不俗的表现。双作用行波热声热泵在低环境温度情况下的这些优点使其非常有潜力成为高端热泵技术。 相似文献
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《低温学》2016
Taconis oscillation is a kind of typical self-excited thermoacoustic oscillation, the study of which is of great significance to reveal the thermoacoustic conversion effect and find ways to suppress self-excited oscillation in cryogenic systems. Based on computational fluid dynamics (CFD) method, the onset process of Taconis oscillation with low temperature hydrogen at atmospheric pressure as working gas is first simulated. It is shown that a standing-wave acoustic field operating at 91 Hz starts spontaneously and finally develops to a saturation state in the Taconis tube with length and inner diameter of 1 m and 0.01 m respectively. Parametric variations in both axial and radial directions of thermoacoustic field are then studied in detail. By combining the computational results with Rott’s theory, the spatial distributions of viscous dissipation, thermal relaxation dissipation, and source/sink terms of Taconis thermoacoustic oscillation are obtained quantitatively. The dissipation and source terms are found to be mainly brought forth by the traveling-wave and standing-wave components of the acoustic field, respectively. 相似文献
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A miniature cascade thermoacoustic engine, which consisted of one standing-wave stage and one traveling-wave stage in series, was built and tested, which length was about 1.2 m, operating at 470 Hz using helium as working gas. The cascade modeling, the simulation and the primary experimental results are described in this paper. Four different configurations of the miniature cascade thermoacoustic engines had been designed and compared. According to the analysis, the diameter ratio of stages was designed to extend the traveling-wave region, which optimized value was about 1.69. The peak-to-peak value of the acoustic pressure was predicted to arrive to 3 bar at the 3 MPa mean pressure of helium when 300 W heating power was the input. The features of the engine were predicted delivering 68 W acoustic power with a thermal efficiency of up to 22.74% (the ratio of acoustic power to heater power). Due to careful designing, the engine self-excited the oscillation smoothly from the first experiment. An onset temperature gradient of about 4.5 K/mm was achieved, and the peak-to-peak acoustic pressure was 48 KPa at the 2 MPa mean pressure when 200 W heating power was the input. The design computation and experimental results showed a rather good agreement between the measured and calculated pressure phasor and temperatures distributions in the cascade thermoaoustic engine. 相似文献