Journal of the Korea Academia-Industrial cooperation Society (한국산학기술학회논문지)

The Korea Academia-Industrial cooperation Society (한국산학기술학회)
권호 표지
DOI QR코드

DOI QR Code

Evaporation Heat Transfer Characteristics of Carbon Dioxide in a Diameter Tube of 4.57mm

내경 4.57mm 관내 CO2의 증발 열전달 특성

  • 손창효 (부경대학교 기계공학부)
  • Published : 2008.06.30
Download PDF
⟨ Previous Next ⟩

Abstract

The evaporation heat transfer coefficient of $CO_2$ (R-744) in a horizontal tube was investigated experimentally. The main components of the refrigerant loop are a receiver, a variable-speed pump, a mass flow meter, a pre-heater and evaporator (test section). The test section consists of a smooth, horizontal stainless steel tube of inner diameter of 4.57mm. The experiments were conducted at mass flux of 400 to $900kg/m^2s$, saturation temperature of 5 to $20^{\circ}C$, and heat flux of 10 to $40kW/m^2$. The test results showed the heat transfer of $CO_2$ has a greater effect on nucleate boiling more than convective boiling. Mass flux of $CO_2$ does not affect nucleate boiling too much. In comparison with test results and existing correlations, All of the existing correlations for the heat transfer coefficient underestimated the experimental data. However Jung et al.'s correlation showed a good agreement with the experimental data. Therefore, it is necessary to develope accurate predictions determining the evaporation heat transfer coefficient of $CO_2$ in horizontal tubes.

수평관내 $CO_2$의 증발 열전달 계수를 실험적으로 조사하였다. 냉매 순환루프의 주요 구성품은 수액기, 변속냉매 펌프, 질량 유량계, 예열기, 증발기(시험부)로 구성된다. 시험부는 내경 4.57 mm의 수평 평활 스텐레스관이다. 실험은 질량유속 $400{\sim}900kg/m^2s$, 포화온도 $5{\sim}20^{\circ}C$, 열유속 $10{\sim}40kW/m^2$인 조건에서 수행하였다. 실험결과로부터 $CO_2$의 열전달은 대류비등보다는 핵비등에 더 많은 영향을 받는 것을 알 수 있었고, $CO_2$의 질량유속은 핵비등에 많은 영향을 미치지 않는 것으로 나타났다. 실험결과와 종래의 상관식을 비교해 본 결과, 기존의 상관식은 실험데이터를 과소예측하였지만, 정 등의 상관식은 좋은 일치를 보였다. 따라서, 수평관내 $CO_2$의 증발 열전달 계수를 예측할 수 있는 정확한 상관식의 개발이 필요하리라 판단된다.

Keywords

References

  1. Thevenot R, A history of refrigeration throughout the world. Paris: IIR; 1979. [Fidler JC, Trans]
  2. Yoon, S. H.(2002), Studies on the characteristics of evaporation and supercritical gas cooling heat transfer of carbon dioxide, Seoul National University, School of Mechanical and Aerospace Engineering, Thesis for the Degree of Doctor of Philosophy.
  3. Yun, L., Kim, Y. C., and Kim, M. S., Two-phase flow patterns of CO2 in a narrow rectangular channel, International Congress of Refrigeration, Washington D. C., pp. 1-7, 2003.
  4. Yun, B., Park, H. Y., Yoo, K. C. and Kim, Y. C., Air-conditioner cycle simulation using tube-by-tube method, Korean Journal of Air-Conditioning and Refrigeration Engineering, Vol. 11, No. 4, pp.499-510, 1999.
  5. Hihara E. and Tanaka S. Boiling heat transfer of carbon dioxide in horizontal tubes. Preliminary proceedings of the 4th IIR-Gustav Lorentzen conference on natural working fluids at Purdue, pp. 279-284, 2000.
  6. Gungor, K. E. and Winterton, R. H. S., Simplified General Correlation for Flow Saturated Boiling and Comparisons of Correlations with Data, Chem. Eng. Res, Des., Vol. 65, pp. 148-156, 1987.
  7. Liu, Z. and Winterton, R. H. S., A General Correlation for Saturated and Subcooled Flow Boiling in Tubes and Annuli, Based on a Nucleate Pool Boiling Equation, Int. J. Heat Mass Transfer, Vol. 34, No. 1, pp. 2759-2766, 1991. https://doi.org/10.1016/0017-9310(91)90234-6
  8. Kandlikar, S. G., A general correlation for saturated two-phase flow boiling horizontal and vertical tubes, Trans. ASME, Vol. 112, pp. 219-228, 1990. https://doi.org/10.1115/1.2910348
  9. Jung, D. S., Mclinden, M., Radermacher, R., and Didion, D., A Study of Flow Boiling Heat Transfer with Refrigerant Mixtures, International Journal of Heat and Mass Transfer, Vol. 32, No. 9, pp. 1751-1764, 1989. https://doi.org/10.1016/0017-9310(89)90057-4