Orifices

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Somchai Wongwises - One of the best experts on this subject based on the ideXlab platform.

  • Review on the experimental studies of refrigerant flow mechanisms inside short-tube Orifices
    International Journal of Refrigeration, 2012
    Co-Authors: Kitti Nilpueng, Somchai Wongwises
    Abstract:

    A short-tube orifice is a kind of an expansion device. The advantages of a short-tube orifice are simplicity, low cost, and low starting torque of the compressor as the pressures across the short-tube orifice equalise during the off-cycle. The two-phase flow mechanisms of refrigerant inside the short-tube orifice are very complicated although its physical configurations are simple. During the past decade, investigations of the mass flow rate of various refrigerants inside short-tube Orifices, which is useful for selecting the proper size in practical applications, have been reported by many researchers. However, few researchers focused on the flow pattern, choked flow, and metastable flow phenomena inside short-tube Orifices, which are necessary for a clear understanding of the flow behaviour and developing suitable calculation techniques. The aim of this paper is to summarise the evolution of the experimental research on refrigerant flow characteristics inside short-tube Orifices to provide guidelines for future research. © 2011 Elsevier Ltd and IIR. All rights reserved.

  • choked flow mechanism of hfc 134a flowing through short tube Orifices
    Experimental Thermal and Fluid Science, 2011
    Co-Authors: Kitti Nilpueng, Somchai Wongwises
    Abstract:

    Abstract This paper is a continuation of the author’s previous work. New experimental data on the occurrence of choked flow phenomenon and mass flow rate of HFC-134a inside short-tube Orifices under choked flow condition are presented. Short-tube Orifices diameters ranging from 0.406 mm to 0.686 mm with lengths ranging from 1 mm to 3 mm which can be applied to a miniature vapour-compression refrigeration system are examined. The experimental results indicated that the occurrence of choked flow phenomena inside short-tube Orifices is different from that obtained from short-tube orifice diameters of greater than 1 mm, which are typically used in air-conditioner. The beginning of choked flow is dependent on the downstream pressure, degree of subcooling, and length-to-diameter ratio. Under choked flow condition, the mass flow rate is greatly varied with the short-tube orifice dimension, but it is slightly affected by the operating conditions. A correlation of mass flow rate through short-tube Orifices is proposed in terms of the dimensionless parameters. The predicted results show good agreement with experimental data with a mean deviation of 4.69%.

Kitti Nilpueng - One of the best experts on this subject based on the ideXlab platform.

  • Review on the experimental studies of refrigerant flow mechanisms inside short-tube Orifices
    International Journal of Refrigeration, 2012
    Co-Authors: Kitti Nilpueng, Somchai Wongwises
    Abstract:

    A short-tube orifice is a kind of an expansion device. The advantages of a short-tube orifice are simplicity, low cost, and low starting torque of the compressor as the pressures across the short-tube orifice equalise during the off-cycle. The two-phase flow mechanisms of refrigerant inside the short-tube orifice are very complicated although its physical configurations are simple. During the past decade, investigations of the mass flow rate of various refrigerants inside short-tube Orifices, which is useful for selecting the proper size in practical applications, have been reported by many researchers. However, few researchers focused on the flow pattern, choked flow, and metastable flow phenomena inside short-tube Orifices, which are necessary for a clear understanding of the flow behaviour and developing suitable calculation techniques. The aim of this paper is to summarise the evolution of the experimental research on refrigerant flow characteristics inside short-tube Orifices to provide guidelines for future research. © 2011 Elsevier Ltd and IIR. All rights reserved.

  • choked flow mechanism of hfc 134a flowing through short tube Orifices
    Experimental Thermal and Fluid Science, 2011
    Co-Authors: Kitti Nilpueng, Somchai Wongwises
    Abstract:

    Abstract This paper is a continuation of the author’s previous work. New experimental data on the occurrence of choked flow phenomenon and mass flow rate of HFC-134a inside short-tube Orifices under choked flow condition are presented. Short-tube Orifices diameters ranging from 0.406 mm to 0.686 mm with lengths ranging from 1 mm to 3 mm which can be applied to a miniature vapour-compression refrigeration system are examined. The experimental results indicated that the occurrence of choked flow phenomena inside short-tube Orifices is different from that obtained from short-tube orifice diameters of greater than 1 mm, which are typically used in air-conditioner. The beginning of choked flow is dependent on the downstream pressure, degree of subcooling, and length-to-diameter ratio. Under choked flow condition, the mass flow rate is greatly varied with the short-tube orifice dimension, but it is slightly affected by the operating conditions. A correlation of mass flow rate through short-tube Orifices is proposed in terms of the dimensionless parameters. The predicted results show good agreement with experimental data with a mean deviation of 4.69%.

Kewen Peng - One of the best experts on this subject based on the ideXlab platform.

  • the self propelled force model of a multi orifice nozzle for radial jet drilling
    Journal of Natural Gas Science and Engineering, 2015
    Co-Authors: Jingbin Li, Xianzhi Song, Zhongwei Huang, Ruiyue Yang, Gensheng Li, Kewen Peng
    Abstract:

    Abstract Radial jet drilling (RJD) is an effective method for the stimulation, exploration, and development of oil and gas resources. The multi-orifice nozzle is a type of highly efficient nozzle applied in RJD. It generates the self-propelled force to pull a connected hose moving forward to form a radial hole. However, there are few studies on the self-propelled ability of the nozzle, and there is no model for the calculation of the self-propelled force. This paper developed a convenient model to calculate the self-propelled force and defined a factor to represent the self-propelled ability of the nozzle. The proposed model was validated by means of experiment and numerical simulation. To achieve a stronger self-propelled ability, we investigated the effects of the number, angle, and diameter of the Orifices on its self-propelled ability. The results show that the forward Orifices exert a negative effect on the self-propelled ability, whereas their angles present a positive effect. With an optimal angle, the backward Orifices primarily generate the self-propelled force. Although an enlarged orifice diameter can improve the performance of the nozzle, it still has an optimal value for the limitation of flow rate and jet pressure. This study provides a reference for the design of multi-orifice nozzles and hydraulic parameters for radial jet drilling technology.

Jongmin Choi - One of the best experts on this subject based on the ideXlab platform.

  • experimental study on characteristics of two phase flow through a bypass orifice expansion device
    International Journal of Air-conditioning and Refrigeration, 2001
    Co-Authors: Jongmin Choi
    Abstract:

    To establish optimum cycle of the inverter-driven heat pump with a variation of frequency, the bypass orifice, which was a short tube having a bypass hole in the middle, was designed and tested. Flow characteristics of the bypass orifice were measured as a function of orifice geometry and operating conditions. Flow trends with respect to frequency were compared with those of short tube Orifices and capillary tubes. Generally, the bypass orifice showed the best flow trends among them, and it would enhance the seasonal energy efficiency ratio of an inverter heat pump system. Based on experimental data, a semiempirical flow model was developed to predict mass flow rate through bypass Orifices. The maximum difference between measured data and model's prediction was within ±5%.

Jingbin Li - One of the best experts on this subject based on the ideXlab platform.

  • the self propelled force model of a multi orifice nozzle for radial jet drilling
    Journal of Natural Gas Science and Engineering, 2015
    Co-Authors: Jingbin Li, Xianzhi Song, Zhongwei Huang, Ruiyue Yang, Gensheng Li, Kewen Peng
    Abstract:

    Abstract Radial jet drilling (RJD) is an effective method for the stimulation, exploration, and development of oil and gas resources. The multi-orifice nozzle is a type of highly efficient nozzle applied in RJD. It generates the self-propelled force to pull a connected hose moving forward to form a radial hole. However, there are few studies on the self-propelled ability of the nozzle, and there is no model for the calculation of the self-propelled force. This paper developed a convenient model to calculate the self-propelled force and defined a factor to represent the self-propelled ability of the nozzle. The proposed model was validated by means of experiment and numerical simulation. To achieve a stronger self-propelled ability, we investigated the effects of the number, angle, and diameter of the Orifices on its self-propelled ability. The results show that the forward Orifices exert a negative effect on the self-propelled ability, whereas their angles present a positive effect. With an optimal angle, the backward Orifices primarily generate the self-propelled force. Although an enlarged orifice diameter can improve the performance of the nozzle, it still has an optimal value for the limitation of flow rate and jet pressure. This study provides a reference for the design of multi-orifice nozzles and hydraulic parameters for radial jet drilling technology.