Publications
27 results found
Xiao L, Luo K, Hu J, et al., 2023, Transient and steady performance analysis of a free-piston Stirling generator, Energy, Vol: 273, ISSN: 0360-5442
Free-piston Stirling generator (FPSG) is a promising distributed power generation system with compact configuration and high efficiency. In a new perspective on thermoacoustics, this paper develops a time-domain acoustic-electrical analogy method to explore the transient and steady-state performance of a highly efficient FPSG. The method captures the main characteristics of the FPSG, simplifying the calculation thus saving time, and its effectiveness has been verified by our experiments. Transient evolutions of key parameters such as volume flow rate, oscillating pressure and voltage, are first given, followed by an investigation of the acoustic field distribution. Subsequently, a performance analysis of the system is carried out. The results indicate that an increase in the damping coefficient leads to a deterioration in performance, particularly for the displacer. Operating parameters have strong influences on system performance: lower ambient temperature, higher heating temperature and larger external electric resistance contribute to higher pressure ratio and electric power, while excellent performance can be achieved at medium mean pressure. A maximum thermal-to-electric efficiency of 45.2% and a highest exergy efficiency of 68.0% are obtained at an electric resistance of 57.5 Ω and a heating temperature of 600 °C, accompanied by an electric power of 1517 W, which implies that the proposed FPSG has great promise in the field of kilowatt-scale distributed power generation. This paper provides a new viewpoint and an effective way for the rapid simulation of free-piston Stirling generator.
Xiao L, Luo K, Zhao D, et al., 2023, Time-domain acoustic-electrical analogy investigation on a high-power traveling-wave thermoacoustic electric generator, ENERGY, Vol: 263, ISSN: 0360-5442
Hu Y, Wang X, Wu Z, et al., 2022, A thermoacoustic cooler with a bypass expansion for distributed-temperature heat loads, APPLIED PHYSICS LETTERS, Vol: 121, ISSN: 0003-6951
Chi J, Xu J, Zhang L, et al., 2021, Study of a gas-liquid-coupled heat-driven room-temperature thermoacoustic refrigerator with different working gases, ENERGY CONVERSION AND MANAGEMENT, Vol: 246, ISSN: 0196-8904
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- Citations: 8
Xu J, Luo E, Hochgreb S, 2021, A thermoacoustic combined cooling, heating, and power (CCHP) system for waste heat and LNG cold energy recovery, ENERGY, Vol: 227, ISSN: 0360-5442
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- Citations: 25
Xu J, Jian S, Kai W, et al., 2020, A hybrid photovoltaic-thermal (PV-T) based combined cooling, heating and power system for tourism sectors in hot climate zones, International Conference on Applied Energy 2020
Xu J, Hu J, Sun Y, et al., 2020, A cascade-looped thermoacoustic driven cryocooler with different-diameter resonance tubes. Part II: Experimental study and comparison, ENERGY, Vol: 207, ISSN: 0360-5442
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- Citations: 14
Xu J, Luo E, Hochgreb S, 2020, Study on a heat-driven thermoacoustic refrigerator for low-grade heat recovery, APPLIED ENERGY, Vol: 271, ISSN: 0306-2619
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- Citations: 34
Xu J, Hu J, Luo E, et al., 2019, A cascade-looped thermoacoustic driven cryocooler with different-diameter resonance tubes. Part I: Theoretical analysis of thermodynamic performance and characteristics, ENERGY, Vol: 181, Pages: 943-953, ISSN: 0360-5442
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- Citations: 16
Xu J, Hu J, Hu J, et al., 2018, Experimental study of a cascade pulse tube cryocooler with a displacer, CRYOGENICS, Vol: 95, Pages: 69-75, ISSN: 0011-2275
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- Citations: 4
Xu J, Hu J, Hu J, et al., 2017, Cascade pulse-tube cryocooler using a displacer for efficient work recovery, CRYOGENICS, Vol: 86, Pages: 112-117, ISSN: 0011-2275
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- Citations: 14
Xu JY, Hu JY, Zhang LM, et al., 2017, A Novel Multi-stage Traveling Wave Thermoacoustically Driven Cryocooler Capable of Multi-stage Power Amplification, Kung Cheng Je Wu Li Hsueh Pao/Journal of Engineering Thermophysics, Vol: 38, Pages: 1597-1602, ISSN: 0253-231X
Looped multi-stage thermacoustically driven cryocoolers are considered as promising candidates for applications in liquefaction and recondensation of natural gas. This paper introduces a new configuration capable of cascade power amplification, which could achieves kW-class cooling power and high thermal-to-cold efficiency at natural gas liquefaction temperature. Based on the classic thermoacoustic theory, a three-stage system is numerically investigated. Firstly, the axis distributions of the acoustic power are presented. Then, a comparison is made between this configuration and the previous multiple-coolers configuration The result shows that, this configuration not only has an advantage of structural simplicity and cooling easy-access, but also comparable to the previous configuration in system performance. In addition, emphasis is put on the influence of some key parameters such as area ratio of resonance tube, resonance tube length and heating temperature, which are found to be critical to the engine performance According to the calculation results, a cooling power of 1478 W and a global exergy efficiency of 12.4% is achieved with 923 K heating temperature and 7 MPa pressurized helium gas. This paper provides significant guidance for future experimental work.
Wang W, Hu J, Xu J, et al., 2017, Influence of the Water-Cooled Heat Exchanger on the Performance of a Pulse Tube Refrigerator, APPLIED SCIENCES-BASEL, Vol: 7
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- Citations: 3
Xu J, Yu G, Zhang L, et al., 2017, Theoretical analysis of two coupling modes of a 300-Hz three-stage thermoacoustically driven cryocooler system at liquid nitrogen temperature range, APPLIED ENERGY, Vol: 185, Pages: 2134-2141, ISSN: 0306-2619
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- Citations: 8
Xu J, Hu J, Zhang L, et al., 2017, Numerical Investigation on a Looped Thermoacoustically-Driven Cryocooler for Natural Gas Liquefaction, Pages: 1725-1729, ISSN: 1876-6102
This paper focuses on a 1 kW-class looped three-stage thermoacoustically-driven cryocooler operating at liquefied natural gas temperature. In this configuration, three identical thermoacoustic engines and one pulse tube cooler are connected by different-diameter resonance tubes. Based on thermoacoustic simulation program, the integral system is designed to achieve high efficiency and large cooling power. Firstly, the optimized dimensions are presented. Acoustic power distribution is then demonstrated to better analysis the energy conversion and transmission process. After that, simulations are performed on the influence of the heating temperature and the mean pressure, which are found to be critical to system performance. The calculated system achieved a cooling capacity of 1170 W and total exergy efficiency of 14.95% at 110 K, showing a good prospect for small-scale NG liquefaction devices.
Xu J, Yu G, Zhang L, et al., 2017, A novel multi-stage looped thermoacoustic heat engine using assembly of elastic membrane and a solid mass, 8th International Conference on Applied Energy (ICAE), Publisher: ELSEVIER SCIENCE BV, Pages: 2028-2032, ISSN: 1876-6102
Xu JY, Hu JY, Long XD, et al., 2017, Study on the influence of a novel shell-tube water-cooled heat exchanger on the performance of pulse tube cooler, Kung Cheng Je Wu Li Hsueh Pao/Journal of Engineering Thermophysics, Vol: 38, Pages: 33-36, ISSN: 0253-231X
This paper introduces a novel shell-tube water-cooled heat exchanger. In this configuration, each larger-diameter copper tube contains four smaller-diameter copper tubes that act as heat-transfer fins, thereby increasing heat transfer area and creating a uniform gas temperature distribution.Contrast experiments are conducted to investigate the system performanceby employing this shell-tube design and previous plated-fin design, under different input power. According to the experimental results, the shell-tube heat exchanger achieves better heat-transfer performance, especially with large input power.With large input power of 2900 W, the system efficiency is increased by 14.8 %by use ofthe shell-tube heat exchanger, and the gas temperature at the inlet of the heat exchanger is decreased by 21 K.
Xu J, Hu J, Zhang L, et al., 2016, A looped three-stage cascade traveling-wave thermoacoustically-driven cryocooler, ENERGY, Vol: 112, Pages: 804-809, ISSN: 0360-5442
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- Citations: 19
Xu J, Hu J, Zhang L, et al., 2016, A novel shell-tube water-cooled heat exchanger for high-capacity pulse-tube coolers, APPLIED THERMAL ENGINEERING, Vol: 106, Pages: 399-404, ISSN: 1359-4311
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- Citations: 6
Xu J, Zhang L, Hu J, et al., 2016, An efficient looped multiple-stage thermoacoustically-driven cryocooler for liquefaction and recondensation of natural gas, ENERGY, Vol: 101, Pages: 427-433, ISSN: 0360-5442
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- Citations: 31
Xu JY, Zhang LM, Hu JY, et al., 2016, A novel thermoacoustically-driven pulse tube cooler capable of energy recovery, Kung Cheng Je Wu Li Hsueh Pao/Journal of Engineering Thermophysics, Vol: 37, Pages: 715-720, ISSN: 0253-231X
A novel thermoacoustically-driven pulse tube cryocooler system has been proposed and investigated in this paper. In this configuration, heat engines are incorporated in a loop, and pulse tube coolers are paralleled to the heat engine. It not only realizes the traveling-wave acoustic field but also power recovery for both heat engines and cryocoolers, leading to the potential of high overall efficiency. Numerical investigations have been conducted on a typical three-stage system based on the thermoacoustic theory. Firstly, emphasis has been put on the influence of the acoustic tube dimensions, and the optimized dimensions are obtained. The distributions of the phase difference and acoustic power, under two different length combination of acoustic tubes, are then presented. Finally, a comparison has been made between this novel configuration and the previous branch configuration. According to the calculated results, this novel configuration significantly achieves superior performance in both cooling power and total exergy efficiency.
Li LY, Wu ZH, Xu JY, et al., 2016, Study on thermoacoustic cryocooler with linear motor type phase adjuster, Kung Cheng Je Wu Li Hsueh Pao/Journal of Engineering Thermophysics, Vol: 37, Pages: 459-465, ISSN: 0253-231X
Optimizing outlet impedance of thermoacoustic cryocooler is one of the key to obtain the best cryocooler performance. In this paper, a thermoacoustic cryocooler with linear motor type phase adjuster is proposed. The linear motor can not only provide a proper phase angle required by a good operation of the thermoacoustic cryocooler, but also convert the expansion work into electricity. Thus, the efficiency of the whole system can be greatly improved. Compared with current technology, this device may have advantages on higher cooling efficiency and simpler structure, which is suitable for large cooling power, high cooling temperature and much expansion work fields. Moreover, it is believed to meet the requirement for heat-driven combined cooling and power application. Based on classical thermoacoustic theories, we analyze the influence of inlet impedance of linear alternator and inlet pressure ratio of cryocooler on the cryocooler performance. On this basis, we build a test platform and construct preliminary experiments. With an average pressure of 3 MPa and a working frequency of 55 Hz, the cryocooler can obtain a cooling power of 158.3 W at 110 K with a relative Carnot efficiency of 16.1%. When electric power is included, a total exergy efficiency of 31.4% is achieved.
Xu J, Hu J, Zhang L, et al., 2015, Effect of coupling position on a looped three-stage thermoacoustically-driven pulse tube cryocooler, ENERGY, Vol: 93, Pages: 994-998, ISSN: 0360-5442
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- Citations: 16
Xu JY, Yu GY, Zhang S, et al., 2015, Investigation on a 300 Hz two-stage pulse tube cooler with random fiber as regenerator material, Kung Cheng Je Wu Li Hsueh Pao/Journal of Engineering Thermophysics, Vol: 36, Pages: 2319-2323, ISSN: 0253-231X
High frequency pulse tube cooler has shown great prospect due to its high power density and high specific power. In this paper, a 300 Hz two-stage pulse tube cooler with random fiber as regenerator material has been numerically investigated. Firstly, the dimensions of the system have been optimized after extensive simulations. With the optimal dimension, the influence of the mean pressure and the inlet pressure ratio on the system performance has been studied. Then, emphasis has been put on the dependence of the wire diameter and the porosity of stainless random fiber on the cooling performance. Furthermore, the stainless steel screen and the stainless random fiber, two kind of the packing materials of the regenerator, have been compared. With the inlet pressure ratio of 1.2, the calculated results show that a no-load temperature of 26.4 K has been achieved in the system filled with 8 μm-wire diameter and 85%-porosity random fiber, which is almost 10 K lower than the no-load temperature in the system filled with stainless steelscreen.
Xu J, Yu G, Zhang L, et al., 2015, Numerical investigation on a 300 Hz pulse tube cryocooler driven by a three-stage traveling-wave thermoacoustic heat engine, CRYOGENICS, Vol: 71, Pages: 68-75, ISSN: 0011-2275
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- Citations: 12
Zhang LM, Hu JY, Wu ZH, et al., 2015, A 1 kW-class multi-stage heat-driven thermoacoustic cryocooler system operating at liquefied natural gas temperature range, APPLIED PHYSICS LETTERS, Vol: 107, ISSN: 0003-6951
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- Citations: 42
Xu J, Yu G, Zhang L, et al., 2015, Numerical investigation on a 300 Hz pulse tube cryocooler driven by a double-acting thermoacoustic heat engine, CLEAN, EFFICIENT AND AFFORDABLE ENERGY FOR A SUSTAINABLE FUTURE, Vol: 75, Pages: 1484-1489, ISSN: 1876-6102
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