• Title/Summary/Keyword: Helium-Bubble generator

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Power Savings of a Refrigerator with 3D-PTV Measurements (3D-PTV에 의한 냉장고 소비전력 저감)

  • Hwang Tae-Gyu;Doh Deog-Hee;Park Seong-Ryong;Bang Yoon-Seok;Yang Min-Cheol;Jang Gyu-Seob;Kim Suk-Roh;Lee Yeon-Won
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.17 no.12
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    • pp.1145-1153
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    • 2005
  • 3D-PTV measurement has been carried out for the inner flows of a refrigerator. To visualize the air flows three-dimensionally, a helium bubble generator has been used for the 3D-PTV measurements. Three-dimensional flow field of the refrigerator's compartments have been reconstructed by the results obtained by the 3D-PTV Measurements on the electric power-consumption was also carried out in order to evaluate the improvements of the flow characteristics. It was verified that $3\%$ of power consumption was saved by improving the flow passages and characteristics.

Distributions of Local Supply and Exhaust Effectiveness according to the Room Airflow Patterns (실내 기류패턴에 따른 급기효율과 배기효율의 분포)

  • 한화택;최선호;장경진
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.9
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    • pp.853-859
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    • 2001
  • A pulsed tracer gas technique is applied to measure distributions of local mean age and residual life time of air in a half-scale experimental chamber. The room airflow patterns are flow-visualized by a Helium bubble generator for three different exhaust locations. A supply slot is located at the top of a right wall, and an exhaust slot is either at bottom-left(Case 1), bottom-right(Case 2), or top-left(Case 3) location. Results show that the distribution of LMA and LMR are different from each other, but both of them are closely related to the airflow pattern in the space. Results on overall room ventilation effectiveness are provided depending upon ventilation airflow rates for three different supply-exhaust configurations.

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Distributions of Local Supply and Exhaust Effectiveness according to Room Airflow Patterns

  • Han, Hwa-Taik;Choi, Sun-Ho;Lee, Woo-Won
    • International Journal of Air-Conditioning and Refrigeration
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    • v.10 no.4
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    • pp.177-183
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    • 2002
  • A pulsed tracer gas technique is applied to measure the distributions of local mean age and local mean residual-life-time of air in a half-scale experimental chamber, The airflow patterns in the chamber are visualized by a Helium bubble generator for three different exhaust locations. A supply slot is located at the top of a right wall, and an exhaust slot is at either bottom-left (Case 1), bottom-right (Case 2), or top-left (Case 3) location. Results show that the distributions of local mean age and local mean residual-life-time are different from each other, but both of them are closely related to the airflow pattern in the space. Included are discussions on explaining the variations of overall room ventilation effectiveness depending upon airflow rates for three different supply-exhaust configurations.

Effect of Ultrasound on the Decomposition of Sodium Dodecylbenzene Sulfonate in Aqueous Solution (Sodium Dodecylbenzene Sulfonate 수용액의 분해반응에서 초음파 효과)

  • Yim, Bong-Been
    • Journal of the Korean Chemical Society
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    • v.48 no.6
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    • pp.561-567
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    • 2004
  • The influence of ultrasound frequency, dissolved gases, and initial concentration on the decomposition of sodium dodecylbenzene sulfonate(DBS) aqueous solution was investigated using ultrasound generator with 200 W ultrasound power. The decomposition rates at three frequencies(50, 200, and 600 kHz) examined under argon atmosphere were highest at 200 kHz. The highest observed decomposition rate at 200 kHz occurred in the presence of oxygen followed by air and argon, helium, and nitrogen. The effect of initial concentration of DBS on the ultrasonic decomposition was decreased with increasing initial concentration and would depend upon the formation of micelle in aqueous solution. It appears that the ultrasound frequency, dissolved gases, and initial concentration play an important role on the sonolysis of DBS. Sonolysis of DBS mainly take place at the interfacial region of cavitation bubbles by both OH radical attack and pyrolysis to alkyl chain, aromatic ring, and headgroup.