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effects of fin arrangement on the melting process in a vertical double-tube heat exchanger considering intermittent boundary conditions
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نویسنده
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mehrannia ali ,taghilou mohammad
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منبع
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aut journal of mechanical engineering - 2023 - دوره : 7 - شماره : 4 - صفحه:319 -338
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چکیده
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This paper presents a numerical analysis of the solid-liquid phase change within a vertical double-tube heat exchanger containing a phase change material, considering intermittent boundary conditions with the application of the enthalpy-porosity technique. to enhance the rate of heat transfer, copper fins are integrated into the inner wall of the heat exchanger in both uniform and non-uniform arrangements. while the uniform placement of fins at equal intervals accelerates the melting process, it leads to a portion of the phase change material remaining solid at the bottom of the heat exchanger due to weakened natural convection. conversely, positioning a greater number of fins with a non-uniform distribution at the bottom of the heat exchanger expedites the overall melting process. it is observed that compared to a finless heat exchanger and under constant boundary temperature, the complete melting time is reduced by 53%, 69%, and 75% for uniform fin distribution, and fin distribution with geometric progression q=2 and q=3, respectively. furthermore, the findings showed that natural convection leads to a greater increase in liquid fraction during melting compared to the assumption of pure conduction. specifically, liquid fraction increases by about 40% with natural convection and around 15% with pure conduction during the first melting period. while the decrease in liquid fraction is almost equivalent for both conditions during freezing.
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کلیدواژه
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vertical double-tube heat exchanger ,phase change material ,non-uniform fin distribution ,intermittent boundary condition
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آدرس
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university of zanjan, department of mechanical engineering, iran, university of zanjan, department of mechanical engineering, iran
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پست الکترونیکی
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taghilou@znu.ac.ir
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Authors
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