A valveless linear compressor was built up to drive a self-made two-stage pulse tube cryocooler. With a designed maximum swept volume of 60 cm3, the compressor can provide the cryocooler with a pressure volume (PV) po...A valveless linear compressor was built up to drive a self-made two-stage pulse tube cryocooler. With a designed maximum swept volume of 60 cm3, the compressor can provide the cryocooler with a pressure volume (PV) power of 400 W. Preliminary measurements of the compressor indicated that both an efficiency of 35%～55% and a pressure ratio of 1.3～1.4 could be obtained. The two-stage pulse tube cryocooler driven by this compressor achieved the lowest temperature of 14.2 K.展开更多
The study on the condensation and the two-phase flow pattern in the condensation section is important to understand the operating mechanisms in a thermosyphon. In this paper, a new electric capacitance tomography(ECT)...The study on the condensation and the two-phase flow pattern in the condensation section is important to understand the operating mechanisms in a thermosyphon. In this paper, a new electric capacitance tomography(ECT) sensor was designed for the visualization measurement in a liquid by removing the shielding case and sealing with insulating hydrophobic material. It was successfully used to measure the condensation process in a thermosyphon under different operating temperatures. The thermosyphon was made of silica glass, and alcohol was used as a working fluid. The alcohol vapor was cooled to condense through the heat convection with the cooling water. The operating temperature was controlled by a heater with different power outputs. The experimental results show that the alcohol vapor condensed in stripes and unevenly on the wall surface at a low operating temperature. The liquid bridge will be formed periodically at the operating temperature of 90?C, and the time interval between two liquid bridges will be shorter with the increase of the operating temperature. At 117?C or even higher operating temperatures, the complete liquid bridge cannot be formed sometimes due to the difference of the growth rate of the surface wave around the circumference.展开更多
文摘A valveless linear compressor was built up to drive a self-made two-stage pulse tube cryocooler. With a designed maximum swept volume of 60 cm3, the compressor can provide the cryocooler with a pressure volume (PV) power of 400 W. Preliminary measurements of the compressor indicated that both an efficiency of 35%～55% and a pressure ratio of 1.3～1.4 could be obtained. The two-stage pulse tube cryocooler driven by this compressor achieved the lowest temperature of 14.2 K.
基金supported by the National Natural Science Foundation of China(No.51206048)the Fundamental Research Funds for the Central Universities(No.13MS11)
文摘The study on the condensation and the two-phase flow pattern in the condensation section is important to understand the operating mechanisms in a thermosyphon. In this paper, a new electric capacitance tomography(ECT) sensor was designed for the visualization measurement in a liquid by removing the shielding case and sealing with insulating hydrophobic material. It was successfully used to measure the condensation process in a thermosyphon under different operating temperatures. The thermosyphon was made of silica glass, and alcohol was used as a working fluid. The alcohol vapor was cooled to condense through the heat convection with the cooling water. The operating temperature was controlled by a heater with different power outputs. The experimental results show that the alcohol vapor condensed in stripes and unevenly on the wall surface at a low operating temperature. The liquid bridge will be formed periodically at the operating temperature of 90?C, and the time interval between two liquid bridges will be shorter with the increase of the operating temperature. At 117?C or even higher operating temperatures, the complete liquid bridge cannot be formed sometimes due to the difference of the growth rate of the surface wave around the circumference.
