CAJ | 학술논문

利用三维稳态湍流数值模拟方法，研究了物性参数为常数的空气在波纹翅片椭圆管和4种不同结构参数的平直‐波纹复合翅片椭圆管换热器翅片间的换热与流阻特性，揭示了空气进口流速（或雷诺数 R e）、平直‐波纹复合翅片中波纹段占有比例以及所处位置对翅片表面平均努塞尔数 Nu、压差损失Δp和翅片管综合换热性能因子 j／f 影响的规律。结果表明，复合翅片中波纹段所处的位置对换热强度的影响显著，但对流动压降（Δp）的影响甚微；复合翅片中波纹翅片所占比例的多少是影响Δp的关键因素；翅片宽度方向平均 Nu（x）的变化主要发生在翅片起始段，不同结构翅片末段的 Nu（x）值相差很小，但此处的波纹翅片却会使总压降增加，即翅片末段宜采用平直翅片；几种翅片椭圆管换热器的综合性能 j／f 均有最佳值产生，起始段为6个波长波纹翅片与末尾段为8个波长的平直翅片形成的复合翅片椭圆管换热器的综合性能最佳。研究结果将对翅片管换热器的选型设计提供理论指导。
이용삼유은태단류수치모의방법，연구료물성삼수위상수적공기재파문시편타원관화4충불동결구삼수적평직‐파문복합시편타원관환열기시편간적환열여류조특성，게시료공기진구류속（혹뢰낙수 R e）、평직‐파문복합시편중파문단점유비례이급소처위치대시편표면평균노새이수 Nu、압차손실Δp화시편관종합환열성능인자 j／f 영향적규률。결과표명，복합시편중파문단소처적위치대환열강도적영향현저，단대류동압강（Δp）적영향심미；복합시편중파문시편소점비례적다소시영향Δp적관건인소；시편관도방향평균 Nu（x）적변화주요발생재시편기시단，불동결구시편말단적 Nu（x）치상차흔소，단차처적파문시편각회사총압강증가，즉시편말단의채용평직시편；궤충시편타원관환열기적종합성능 j／f 균유최가치산생，기시단위6개파장파문시편여말미단위8개파장적평직시편형성적복합시편타원관환열기적종합성능최가。연구결과장대시편관환열기적선형설계제공이론지도。
A 3‐D steady and turbulent numerical simulation was employed to investigate the flow and heat transfer characteristics of air ,having constant properties ,in fin‐and‐oval tube heat exchangers with wavy fin or wavy‐plain combined fin .The investigation reveals the effect of air inlet velocity or Reynolds number (Re) ,wavy fin proportion and location in the combined fin on the average Nusselt number (Nu) of the whole fin surface ,the pressure loss(Δp) and the coeffi‐cient of performance (j/f ) .It is found that ,within the studied Re range ,the wavy location in conbined fin has a significant influence on the Nu ,but has little effect on the Δp ;however ,the wavy fin proportion is a key factor for the Δp .The change of average Nusselt number in the width direction(Nu(x)) along flow direction occurs mainly at the fin leading edge ,and the Nu(x) has a smaller difference at the fin rear section for different fin configurations .So it is more suit‐able to locate plain fin to the rear section rather than wavy fin ,which can further reduce the pres‐sure loss penalty w hile maintains the enhanced heat transfer .For all studied objects ,the optimum j/f can be achieved .The finned oval tube heat exchanger with a combination of 6 wavelength wavy fin and 8 wavelength plain fin arranged along flow direction has maximum j/f value .