Design, Fabrication and Heat Transfer Analysis of a Mesoscopic Pulse Tube as an Integrated Micro-Refrigeration System

2000 ◽  
Author(s):  
Ninad Shinde ◽  
Rashid Bashir ◽  
Eckhard Groll ◽  
George Chiu

Abstract The phenomenon of surface heat pumping has been widely used to accomplish refrigeration in macro-scale devices such as pulse-tubes and thermo-acoustic devices. Pulse tube refrigerators are typically used to lift heat at cryogenic temperatures. The advantage of a pulse tube as a no moving part device makes it amenable to miniaturization at dimensional scales where areal effects, such as friction and viscosity, dominate. In this paper, the design and preliminary fabrication results of such a device to investigate the effect of surface heat pumping in mesoscopic glass channels are presented.

Author(s):  
Chandramoulee Krishnamoorthy ◽  
Rahul P. Rao ◽  
Afshin J. Ghajar

This review paper specifically concentrates on heat transfer in micro-tubes and eleven experiments (on liquid flow) and two experiments (on gaseous flow) from 1991 to 2007 are reviewed critically with respect to measurement techniques, instrumentation; and factors like surface roughness and diameter that may play an important role at these small scales. Moreover, a comprehensive list of numerical and analytical results (for both liquid and gaseous flows) is presented in this paper. Interestingly, the effect of surface roughness on heat transfer does not seem to have been investigated thoroughly, as it has been observed to play a key role in influencing heat transfer at small diameters. The state-of-art review thus provides the contemporary experimenters in the field of mini-micro channel heat transfer, this tabulated data that can be used to understand how the different parameters affect the heat transfer in these small scales and a data-bank to validate future numerical and experimental work. The present study identifies the various factors that have contributed in the disparity of results found in the literature and finds that there is a need to investigate certain issues like the effects of roughness, diameter, and secondary flow due to buoyancy on heat transfer and transition. Moreover, it was observed that the start and end of the transition region at these small diameters are not validated by the any of the existing macro-scale correlations.


Author(s):  
Takao Koshimizu ◽  
Hiromi Kubota ◽  
Yasuyuki Takata ◽  
Takehiro Ito

The working principle of refrigeration in basic pulse-tube refrigerators (BPTR) has been explained by the mechanism called surface heat pumping (SHP) that heat is conveyed from the cold end to the hot end of the pulse tube by the successive heat exchange between the working gas and the wall. In this study, a numerical simulation has been performed to clarify the effect of the wall in BPTRs by comparing the numerical results in two physical models; one is the model considering the heat exchange between the working gas and the wall (HE model), and the other is the model ignoring that (AW model). As a result, the importance in the effect of the wall was shown clearly. In addition, the mechanism of refrigeration other than the SHP was made clear in the AW model.


Author(s):  
Takao Koshimizu ◽  
Hiromi Kubota ◽  
Yasuyuki Takata ◽  
Takehiro Ito

Numerical simulation of heat and fluid flow in a basic and an orifice pulse tube refrigerator have been performed to visualize heat pumping generated in the regenerator and the pulse tube, and to clarify the difference in heat pumping caused by the phase difference between pressure and displacement of gas. Common components of the regenerator and the pulse tube are used in the basic and the orifice pulse tube refrigerator. The flow in the tube is assumed to be one-dimensional and compressible. As governing equations, the continuity, momentum and energy equations are used in this study. From the temperature and velocity field obtained as a result of the simulation, the relation between the displacement and the temperature change of gas elements is visually clarified, and consequently it is found that the characteristic that the temperatures of gas elements are nearly higher than those of the regenerator material or the pulse-tube wall during compression and lower during expansion is very important for the heat pumping in basic and orifice pulse tube refrigerators. Furthermore, the behavior of heat pumping in the basic and the orifice pulse tube refrigerator is illustrated by analyzing the relation between the displacement of gas elements and heat quantity transferred to the wall from the gas elements, and the difference in heat pumping between the basic and the orifice pulse tube refrigerator is made clear.


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