Browsing by Author "Smith, Gerrit Rohlandt"
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- ItemBuilding, testing and modelling of a pulse tube cryogenic cooler(Stellenbosch : Stellenbosch University, 2006-12) Smith, Gerrit Rohlandt; Dobson, R. T.; Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering.ENGLISH ABSTRACT: Pulse tube cryogenic coolers (cryocoolers) are among the latest innovations of cryogenic coolers. They fall in the same category as the reversed Stirling cycle cryocoolers that have been used for decades to cool infrared detectors in military and space applications. Pulse tube cryocoolers will replace most of the Stirling cryocoolers in future applications, because they have no moving parts at its cold point and therefore are subject to less vibrations, and hence has a longer service life. Pulse tube coolers, like domestic refrigerators, are also driven by a compressor. The type of compressor used in this project is of the reciprocating type which is driven by a linear, resonant motor which is similar to a loudspeaker mechanism. This project is about the building, testing and mathematical modelling of a pulse tube cryogenic cooler. The pulse tube cryocooler and its reciprocator (reciprocating compressor) was designed and manufactured. Numerous tests were conducted to evaluate the reciprocator. A complete mathematical model is presented for the reciprocator which was compared with the data obtained from the tests. The pulse tube cryocooler was modelled with a one-dimensional, time dependant CFO (computational fluid dynamics) model by solving the discretized conservation equations which were derived in this project from first principles. The discussions and conclusions regarding these results are presented, together with recommendations for future work.