• Title/Summary/Keyword: Hot Air Bubbles

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A Study on the Heat Release Characteristics of Gel Type Micro Size Latent Heat Storage Material Slurry with Direct Contact Heat Exchange Method (겔 상태의 미세 잠열 축열재 혼합수의 기액직접접촉식 열교환법에 의한 방열 특성)

  • 김명준
    • Journal of Advanced Marine Engineering and Technology
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    • v.28 no.4
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    • pp.618-623
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    • 2004
  • This paper has dealt with the heat storage characteristics of gel type micro size latent heat storage material slurry. The heat release operation to the gel type micro size latent heat storage material slurry was carried out using hot air bubbles by direct contact heat exchange. This experiment was carried out using phase change material of n-paraffin so the heat release amount is higher than cold water system. The parameters of this experiment were concentration of latent heat phase change material, height of heat release bath and inlet velocity of hot air. The main results obtained are as follows : (1) The effect of concentration of latent heat phase change material dispersed with water is very affective to the direct contact heat exchange between hot air and gel type micro size latent heat storage material slurry. (2) It is clarified that the most effective concentration of latent heat phase change material dispersed with water exists around 20mass% at this type of direct heat exchange model experiment.

Development of High Performance Bubble Jet Loop Heat Pipe for Hot Water Floor Heating System (온수 가열 바닥 난방 시스템용 고성능 버블젯 루프 히트파이프 개발)

  • Kim, Jong-Soo;Kwon, Yong-Ha;Kim, Jeong-Woong
    • Journal of Power System Engineering
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    • v.18 no.4
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    • pp.23-28
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    • 2014
  • In order to increase the performance of conventional hot water floor heating system, the bubble jet loop heat pipe for the system was developed. This experiment was conducted under next conditions : Working fluid was R-134a, charging ratio was 50%. A temperature of hot water, room temperature and flow rate were $60^{\circ}C$, $15^{\circ}C$ and 0.5~1.5 kg/min, respectively. The experimental results, show that bubble jet loop heat pipe had a high effective thermal conductivity of $4714kW/m^{\circ}C$ and a sufficient heat flux of $73W/m^2$ to heat the floor to $35^{\circ}C$ in case of the 1.5 kg/min of flow rate. So the bubble jet loop heat pipe has a possibility for appling of the floor heating system. Additionally, the visualization of bubble jet loop heat pipe was performed to understand the operating principle. Bubbles made by the narrow gap between inner tube and outer tube of evaporating part generate pulsation at liquid surface of working fluid. The pulsation had slug flow and wavy flow. So working fluid circulates in the bubble jet loop heat pipe as two phase flow pattern. And large amount of heat is transferred by the latent heat from evaporating part to condensing part.

Rewriting Georgic: Anna Letitia Barbauld's "Washing-Day" (죠직 다시 쓰기 -아나 레티셔 바볼드의 「빨래하는 날」)

  • Shin, Kyung-Sook
    • Journal of English Language & Literature
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    • v.56 no.5
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    • pp.947-971
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    • 2010
  • Anna Letitia Barbauld's poem "Washing-Day" (1797) has sparked a variety of feminist critical endeavors over the past two decades. While many feminist literary critics try to salvage the poem as a successful tongue-in-cheek riposte directed at the male dominant literary world, more rigorous Marxist feminists accuse Barbauld of being limited by her own middle-class woman's view on women's domestic labor. Legitimate as they may be, these readings fail to elucidate Barbauld's place in a larger literary and intellectual discourse during the eighteenth century. In this paper I read "Washing-Day" as a woman's georgic, a genre or mode concerned with agricultural labor, the public value of which was highly recognized in eighteenth-century England. Alluding to canonical texts by writers like Shakespeare, Milton, and Pope, Barbauld's "loaded lines" in mock-heroic form create a space in which the women's domestic labor of washing interrupts men's daily routines and disrupts their poetic assumptions. While she makes women's work visible, Barbauld also addresses its quintessential nature. Women's work is affective labor; women have to labor physically and mentally to produce the desired domestic comfort. By allowing the image of the soap "bubble" to echo with many "bubbles" in other writers' texts, from the soap bubbles the narrator used to play with as a child to the hot-air balloon "bubble" of the Montgolfier brothers, Barbauld pleasantly equates work and day-dreaming, men's toil and children's play, and finally public, scientific, and recognized labor and private, domestic, and imaginative activities.