Optimizing Thermal Efficiencies of Power-Law Fluids in Double-Pass Concentric Circular Heat Exchangers with Sinusoidal Wall Fluxes
學年 110
學期 2
出版（發表）日期 2022-06-16
作品名稱 Optimizing Thermal Efficiencies of Power-Law Fluids in Double-Pass Concentric Circular Heat Exchangers with Sinusoidal Wall Fluxes
作品名稱（其他語言）
著者 Chii-Dong Ho; Jr-Wei Tu; Hsuan Chang; Li-Pang Lin; Thiam Leng Chew
單位
出版者
著錄名稱、卷期、頁數 Mathematical Biosciences and Engineering 19(9), p.8648−8670
摘要 Effect of external-recycle operations on the heat-transfer efficiency, specifically for the power-law fluid flowing in double-pass concentric circular heat exchanger under sinusoidal wall fluxes, is investigated theoretically in the developed countries. Given that the fluid is heated twice on both sides of the impermeable sheet, four flow patterns proposed in recycling double-pass operations are expected to make substantial improvements in the performance of heat exchanger device in this study. Theoretical predictions point out that the heat-transfer efficiency increases with the ratio of channel thickness of double-pass concentric circular heat exchanger for all new designs under the same working dimension and the operational condition. The fluid velocity within the double-pass heat exchanger is increased by the fluids flowing through divided subchannels, which contributed to the higher convective heat-transfer efficiency. A simplified mathematical formulation was derived for double-pass concentric circular heat exchangers and would be a significant contribution to analyze heat transfer problems with sinusoidal wall fluxes at boundaries. The results deliver the optimal performance for the proposed four configurations with the use of external recycle compared to those conducted in single-pass, where an impermeable sheet is not inserted. The influences of power-law index and impermeable-sheet position on average Nusselt numbers under various flow patterns are also delineated. The distribution of dimensionless wall temperature was lower at the level of relative smaller thickness of annular channel, and the average Nusselt numbers for four external-recycle configurations and single-pass device were more suitable for operating under same condition. The ratio of the power consumption increment to heat-transfer efficiency enhancement demonstrates the economic feasibility among various configurations of double-pass concentric circular heat exchanger. The results also show that the external-recycle configuration (say Type B in the present study) serves as an important economic advantage in designing concentric circular heat exchangers for heating power-law fluids due to the smaller volumetric flow rate in annular channel with exiting outlet temperature.
關鍵字 conjugated graetz problem;external recycle;heat-transfer efficiency;power-law fluids;sinusoidal wall fluxes
語言 en_US
ISSN 1551-0018
期刊性質 國外
收錄於 SCI EI
產學合作
通訊作者
審稿制度 是
國別 USA
公開徵稿
出版型式 ,電子版
SDGS 潔淨水與衛生,可負擔的潔淨能源