The Experts below are selected from a list of 129 Experts worldwide ranked by ideXlab platform

Richard Kelso - One of the best experts on this subject based on the ideXlab platform.

  • experimental study of the flow structure in a counter flow ranque hilsch vortex tube
    International Journal of Heat and Mass Transfer, 2012
    Co-Authors: Maziar Arjomandi, Richard Kelso
    Abstract:

    Abstract The mechanism of the temperature separation in a Ranque–Hilsch vortex tube has been investigated since the discovery of this phenomenon. In spite of being investigated by many researchers, no consensus has yet been reached regarding the mechanism’s hypothesis. This paper reports on a study in progress exploring the temperature separation in a counter-flow vortex tube. The effects of the geometrical parameters, including Inlet Nozzles, cold exit, hot exit and length of the tube, were investigated, which indicated the settings for the best performance of the vortex tube. Flow properties in the vortex tube were measured and used to understand the flow structure inside the tube. Accurate measurements of the three-dimensional velocity distribution in the tube were conducted. The results provided enough evidence that the flow in the tube consists of a forced vortex formed near the Inlet gradually transforming to a free vortex at the hot end. Experimental results found in this research show the vortex transformation along the tube and support the hypothesis proposed in previous study.

Vaclav Tesař - One of the best experts on this subject based on the ideXlab platform.

  • validation of boundary layer model of pressure drop on chamfered Inlet Nozzles
    Sensors and Actuators A-physical, 2018
    Co-Authors: Vaclav Tesař
    Abstract:

    Abstract This paper concerns a family of simple subsonic axially symmetric Nozzles with chamfered entrance into the constant-diameter exit channel. This geometry is a compromise between expensive high-performance Nozzles with smoothly curved internal walls and simple drilled holes. Pressure loss data obtained earlier in experiments and now in numerical flowfield computations were processed using a boundary-layer model of nozzle behaviour. Very good agreements corroborate the overall analysis.

Maziar Arjomandi - One of the best experts on this subject based on the ideXlab platform.

  • experimental study of the flow structure in a counter flow ranque hilsch vortex tube
    International Journal of Heat and Mass Transfer, 2012
    Co-Authors: Maziar Arjomandi, Richard Kelso
    Abstract:

    Abstract The mechanism of the temperature separation in a Ranque–Hilsch vortex tube has been investigated since the discovery of this phenomenon. In spite of being investigated by many researchers, no consensus has yet been reached regarding the mechanism’s hypothesis. This paper reports on a study in progress exploring the temperature separation in a counter-flow vortex tube. The effects of the geometrical parameters, including Inlet Nozzles, cold exit, hot exit and length of the tube, were investigated, which indicated the settings for the best performance of the vortex tube. Flow properties in the vortex tube were measured and used to understand the flow structure inside the tube. Accurate measurements of the three-dimensional velocity distribution in the tube were conducted. The results provided enough evidence that the flow in the tube consists of a forced vortex formed near the Inlet gradually transforming to a free vortex at the hot end. Experimental results found in this research show the vortex transformation along the tube and support the hypothesis proposed in previous study.

J. Prabakaran - One of the best experts on this subject based on the ideXlab platform.

Pongjet Promvonge - One of the best experts on this subject based on the ideXlab platform.

  • Review of Ranque-Hilsch effects in vortex tubes
    Renewable & Sustainable Energy Reviews, 2008
    Co-Authors: Smith Eiamsa-ard, Pongjet Promvonge
    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.

  • Simulation of thermal separation in a high-velocity vortex-type flow.
    2007
    Co-Authors: Smith Eiamsa-ard, S Pethkool, Pongjet Promvonge
    Abstract:

    The Ranque-Hilsch vortex tube (or vortex tube) is a device for producing the hot and cold air when the compressed air flows tangentially into the vortex chamber through the Inlet Nozzles. The application of a mathematical model for the simulation of a strongly swirling flow in a vortex tube is presented. A staggered finite volume approach with the standard k-epsilon model and an algebraic Reynolds stress model (ASM) for 2D compressible, axisymmetrical flows was used to carry out all the computations. Due to the simple geometry and availability of experimental data, a uni-flow vortex tube was simulated to study its velocity field and temperature/energy separation. It is found that a temperature separation in the tube exists and predictions of the temperature fields agree well with measurements. To understand the effects of these tube parameters clearly, a numerical computation was carried out to examine the influence of Inlet nozzle locations on temperature separation.

  • investigation on the vortex thermal separation in a vortex tube refrigerator
    2005
    Co-Authors: Pongjet Promvonge, Smith Eiamsaard
    Abstract:

    This paper describes the experimental study of the temperature separation phenomenon in a counter-flow type vortex tube. Effects of (1) the number of Inlet tangential Nozzles, (2) the cold orifice diameter, and (3) tube insulations on the temperature reduction and isentropic efficiency of the tube were experimentally investigated. The temperature drops of the cold air obtained from these tests were in good agreement with available data for comparison at a similar scale of operating conditions. The experimental results showed that the insulated vortex tube with 4 Inlet Nozzles and cold orifice diameter of 0.5D yielded the highest temperature reduction (temperature separation) and isentropic efficiency at about 30 o C and 33% respectively.