Abstract A novel configuration of compact cross-flow helical tube (CFHT) heat exchanger for cooling applications is proposed, in view of its inherent high surface area density and tortuous flow path. The cooling potential of such a configuration is assessed against that of its straight tube counterpart i.e., cross-flow straight tube (CFST) heat exchanger for similar volumetric air flow rates under laminar regime. Cross-flow experiments are conducted on CFST and CFHT unit systems for different helix angles ranging from 46∘ ≤ φ ≤ 72∘. CFHT exhibits superior cooling potential, with a manifold increase in heat extracted per unit volume of heat exchanger, as high as 1.5-3.3 times, and heat exchanger efficiency as high as 70% (for φ = 72 ∘ ). The comparative assessment is extended to an array of (3 × 3) tubes in an inline arrangement, through CFD analysis, for a wider range of helix angles from 17∘ ≤ φ ≤ 72∘. Analysis reveals (i) flow intensification reflected in ~2.3 times increase in Re and (ii) 3D flow that eliminates dead zones otherwise observed behind the straight tubes. The flow features result in 1.4-2.5 times increase in Nu, 2-4 times increase in the rate of heat extracted and higher heat exchanger efficiency upto 90%. Thereby, the efficacy of CFHT heat exchanger in cooling applications is established.

中文翻译：

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通过更高的面密度和流动曲率在紧凑型螺旋管横流换热器中增强冷却

摘要 鉴于其固有的高表面积密度和曲折的流动路径，提出了一种用于冷却应用的紧凑型错流螺旋管 (CFHT) 换热器的新型配置。这种配置的冷却潜力是根据其直管对应物（即，错流直管 (CFST) 换热器在层流状态下的类似体积空气流速）进行评估的。在 CFST 和 CFHT 单元系统上对 46∘ ≤ φ ≤ 72∘ 的不同螺旋角进行了错流实验。CFHT表现出优越的冷却潜力，单位体积换热器提取的热量成倍增加，高达1.5-3.3倍，换热效率高达70%（对于φ = 72 ∘ ）。比较评估扩展到串联排列的 (3 × 3) 管阵列，通过 CFD 分析，从 17∘ ≤ φ ≤ 72∘ 的范围更广的螺旋角。分析显示 (i) 流动增强反映在 Re 增加约 2.3 倍和 (ii) 3D 流动，消除了在直管后面观察到的死区。流动特性使Nu增加1.4-2.5倍，提取热量增加2-4倍，换热效率高达90%。因此，确定了 CFHT 换热器在冷却应用中的功效。取热量提高2-4倍，换热效率高达90%。因此，确定了 CFHT 换热器在冷却应用中的功效。取热量提高2-4倍，换热效率高达90%。因此，确定了 CFHT 换热器在冷却应用中的功效。