scispace - formally typeset
Search or ask a question
Author

de Atam Fons Waele

Bio: de Atam Fons Waele is an academic researcher from Eindhoven University of Technology. The author has contributed to research in topics: Regenerative heat exchanger & Thermal conduction. The author has an hindex of 16, co-authored 50 publications receiving 1137 citations.

Papers
More filters
Journal ArticleDOI
TL;DR: The design strategy described in this paper is a guide for the design and development of thermoacoustic coolers and the optimization of the different parts of the refrigerator will be discussed.

165 citations

Journal ArticleDOI
TL;DR: In this paper, a simple vortex tube is built and nitrogen is used as its working fluid, and a special Pitot tube is used for the measurement of the pressure and velocity.

154 citations

Journal ArticleDOI
TL;DR: In this paper, the authors describe the construction and performance of a thermoacoustic refrigerator, which consists of three major parts: the refrigerator, the electronic apparatus necessary for the measurements and acquisition of the experimental data, and the gas-control panel which is used to fill and purge the system and to prepare gas mixtures.

100 citations

Journal ArticleDOI
TL;DR: A quantitative experimental investigation into the effect of the pore dimensions on the performance of thermoacoustic devices is reported and it is concluded that a plate spacing in the stack of about three times the penetration depth should be optimal for thermoACoustic refrigeration.
Abstract: The characteristic pore dimension in the stack is an important parameter in the design of thermoacoustic refrigerators. A quantitative experimental investigation into the effect of the pore dimensions on the performance of thermoacoustic devices is reported. Parallel-plate stacks with a plate spacing varying between 0.15 and 0.7 mm are manufactured and measured. The performance measurements show that a plate spacing in the stack of 0.25 mm (2.5 deltak) is optimum for the cooling power. A spacing of 0.4 mm (4 deltak) leads to the lowest temperature. The optimum spacing for the performance is about 0.3 mm (3 deltak). It is concluded that a plate spacing in the stack of about three times the penetration depth should be optimal (3 deltak) for thermoacoustic refrigeration.

96 citations

Journal ArticleDOI
TL;DR: In this paper, a three-stage pulse tube refrigerator was constructed with a rotary valve to generate the pressure oscillations and achieved a minimum average temperature of 2.19 K. This is the lowest temperature achieved by mechanical refrigerators.

75 citations


Cited by
More filters
Proceedings Article
14 Jul 1996
TL;DR: The striking signature of Bose condensation was the sudden appearance of a bimodal velocity distribution below the critical temperature of ~2µK.
Abstract: Bose-Einstein condensation (BEC) has been observed in a dilute gas of sodium atoms. A Bose-Einstein condensate consists of a macroscopic population of the ground state of the system, and is a coherent state of matter. In an ideal gas, this phase transition is purely quantum-statistical. The study of BEC in weakly interacting systems which can be controlled and observed with precision holds the promise of revealing new macroscopic quantum phenomena that can be understood from first principles.

3,530 citations

Journal ArticleDOI
TL;DR: In this paper, the physical properties of diluted magnetic semiconductors (DMS) of the type AII1−xMnxBVI (e.g., Cd1−mnxSe, Hg 1−mnsTe) were reviewed.
Abstract: We review the physical properties of diluted magnetic semiconductors (DMS) of the type AII1−xMnxBVI (e.g., Cd1−xMnxSe, Hg1−xMnxTe). Crystallographic properties are discussed first, with emphasis on the common structural features which these materials have as a result of tetrahedral bonding. We then describe the band structure of the AII1−xMnxBVI alloys in the absence of an external magnetic field, stressing the close relationship of the sp electron bands in these materials to the band structure of the nonmagnetic AIIBVI ‘‘parent’’ semiconductors. In addition, the characteristics of the narrow (nearly localized) band arising from the half‐filled Mn 3d5 shells are described, along with their profound effect on the optical properties of DMS. We then describe our present understanding of the magnetic properties of the AII1−xMnxBVI alloys. In particular, we discuss the mechanism of the Mn++‐Mn++ exchange, which underlies the magnetism of these materials; we present an analytic formulation for the magnetic susc...

2,895 citations

01 Jan 2007

1,932 citations

Journal ArticleDOI
TL;DR: In this article, the authors present an overview of the phenomena occurring inside the vortex tube during the temperature/energy separation on both the counter flow and parallel flow types, and present several different hypotheses based on experimental, analytical, and numerical studies.
Abstract: The vortex tube or Ranque–Hilsch vortex tube is a device that enables the separation of hot and cold air as compressed air flows tangentially into the vortex chamber through inlet nozzles. Separating cold and hot airs by using the principles of the vortex tube can be applied to industrial applications such as cooling equipment in CNC machines, refrigerators, cooling suits, heating processes, etc. The vortex tube is well-suited for these applications because it is simple, compact, light, quiet, and does not use Freon or other refrigerants (CFCs/HCFCs). It has no moving parts and does not break or wear and therefore requires little maintenance. Thus, this paper presents an overview of the phenomena occurring inside the vortex tube during the temperature/energy separation on both the counter flow and parallel flow types. The paper also reviews the experiments and the calculations presented in previous studies on temperature separation in the vortex tube. The experiment consisted of two important parameters, the first is the geometrical characteristics of the vortex tube (for example, the diameter and length of the hot and cold tubes, the diameter of the cold orifice, shape of the hot (divergent) tube, number of inlet nozzles, shape of the inlet nozzles, and shape of the cone valve. The second is focused on the thermo-physical parameters such as inlet gas pressure, cold mass fraction, moisture of inlet gas, and type of gas (air, oxygen, helium, and methane). For each parameter, the temperature separation mechanism and the flow-field inside the vortex tubes is explored by measuring the pressure, velocity, and temperature fields. The computation review is concentrated on the quantitative, theoretical, analytical, and numerical (finite volume method) aspects of the study. Although many experimental and numerical studies on the vortex tubes have been made, the physical behaviour of the flow is not fully understood due to its complexity and the lack of consistency in the experimental findings. Furthermore, several different hypotheses based on experimental, analytical, and numerical studies have been put forward to describe the thermal separation phenomenon.

226 citations

Journal ArticleDOI
TL;DR: In this article, the status of the theory and experiment which can contribute to our knowledge of plasmon excitations in synthetic semiconductor heterostructures is surveyed. But, beyond the presentation of the results achieved, there is a need to examine carefully the methodologies employed to obtain such results.

196 citations