The Vuilleumier cryocooler is a heat engine which uses heat energy rather for the machine, and detailes of design based an isothermal thermodynamic cycle. PDF | A detailed experimental results of one-stage VM cryocooler with Experimental study on a one-stage Vuilleumier cryocooler with large pressure ratio VM-PT cryocooler can be designed in several configurations. Download Citation on ResearchGate | Study of a Vuilleumier cycle cryogenic This effort led to the selection of an optimum refrigerator design for the LSIR the feasibility of using a Vuilleumier cryocooler to cool a flight-type detector .
|Published (Last):||17 September 2006|
|PDF File Size:||2.8 Mb|
|ePub File Size:||8.11 Mb|
|Price:||Free* [*Free Regsitration Required]|
The pressure variations in the cold head are obtained by connecting it periodically to the high- and low-pressure sides of a compressor by a rotating valve. February 17, Released: It leaves the heat exchanger at room temperature point a. A Cryocooler is a standalone cooler, usually of cryocooler size. The thermodynamic and hydrodynamic properties of regenerators are very complicated, so one usually makes simplifying models.
This paper describes the specifications required for the machine, and detailes of design based an isothermal thermodynamic cycle. In order to keep the system in the steady state gas is supplied to compensate for the liquid fraction x lf has been removed.
The cooling cycle is split in 4 steps as depicted in Fig. Its position is synchronized with the motion of the displacer. Basically it is a very simple type of cooler which is widely applied as cryocooler or as the final stage of liquefactors. The basic type of Stirling-type cooler is depicted in Fig.
February 25, received: This leads to losses. Usually the motions of both pistons are driven by a common rotary axes which makes the motions harmonic. The Vuilleumier cryocooler is a heat engine which uses heat energy rather than mechanical energy to cyclically pressurize the working gas.
Helium at pressures in the 10 to 30 bar range is the working fluid. When used as a cryocooler it is preferable to use gas mixtures instead of pure nitrogen. In the pV diagram Fig. This page was last edited on 13 Decemberat Left and right the thermal contact cuilleumier the surroundings at the temperatures T a and T L is supposed to be perfect so that the compression and expansion are isothermal.
From Wikipedia, the free encyclopedia. Or the inlet of the compressor the gas is at room temperature K and a pressure of vuipleumier bar point a. No work is required to move the displacer since, ideally there is no pressure drop over it.
A more detailed description of Joule-Thomson coolers and Joule-Thomson refrigerators can be found in . Basically cheap compressors of domestic refrigerators can be used, but one must prevent overheating of the compressor as it is not designed for helium.
Already have an account?
Demonstration testing of a Vuilleumier cryocooler with an integral
Ideal heat exchangers have no flow resistance and the exit gas temperature is the same as the fixed vuilleumuer temperature T X of the heat exchanger. The liquid fraction is x. A review is given by Radebaugh. The cycle starts with the low-pressure lp valve closed, the high-pressure hp valve open, and the displacer all the way to the right so in the cold region.
Usually helium is the working fluid. In its most extreme form an ideal regenerator has the following properties:. The recent progress in the cryocooler field is for a great deal due to the development of new materials with a high heat capacity below 10K. A schematic diagram of a JT liquefier, is given in Fig. Transactions of the Japan Society of Mechanical Engineers.
A regenerator consists of a matrix of a solid porous material, such as granular particles or metal sieves, through which gas flows back and forth. Cryoccooler of the Society of Mechanical Engineers. Periodically heat is stored and released by the material. They provide stiffness in the radial direction and flexibility in the axial direction. As typical performance values from the calculation, the machine has a cooling capacity of 2. The weight of the complete cesign was 6 kg. An important component of refrigerators, operating with oscillatory flows, is the regenerator.
Views Read Edit View history. Cyrocooler the JT expansion, point d, it has a temperature of The pulse tube refrigerator is treated in a separate article. A displacer is a solid body which moves back and forth in the cold head driving the gas back and forth between the warm and the cold end of the cold head via the regenerator. The cold head contains a compression and expansion space, a regenerator, and a displacer.
The regenerator in the cold finger is suspended by a spring. This is a clear disadvantage of this type of cooler. In practice the cycle is not divided in discrete steps as described above.
Another type of Stirling cooler is the split-pair type Fig. Heat exchangers are important cryofooler of all cryocoolers. Usually the regenerator and the displacer are combined in one body. In this way the swept volume of the compressor can be 50 60 times smaller than of the cooler. The analytical model can be used to clarity the working gas behavior in the system and determine the performance characteristics of the machine by calculating all losses to be mutually decoupled.