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  本文關鍵詞：基于扭帶或錐形環(huán)的管內強化傳熱的數(shù)值模擬　出處：《華中科技大學》2015年碩士論文　論文類型：學位論文

  更多相關文章： 數(shù)值模擬 交替軸扭帶 窄邊扭帶 中空扭帶 錐形環(huán)

【摘要】：管內強化傳熱技術是工業(yè)中一種常用的節(jié)能技術手段,廣泛運用于能源、化工、電子、醫(yī)藥、材料等領域。因此,開發(fā)新的強化傳熱技術,提高設備的換熱效率對于節(jié)能和經(jīng)濟的發(fā)展都具有重要作用。本文在前人對窄邊扭帶研究的基礎上,設計了交替軸窄邊扭帶、交替軸窄邊中空扭帶和交替軸貼壁中空扭帶,并對管內內置上述形式的扭帶在層流條件下進行了數(shù)值模擬,結果表明:對于交替軸窄邊扭帶和交替軸窄邊中空扭帶,在較低Re下,Nu隨扭帶錯位角的增大而增大,而Re較高時,不同錯位角度之間的差別很小,f隨錯位角的變化差別不大,PEC最大對應的是90°交錯角。對于交替軸貼壁中空扭帶,60°交錯角下的Nu最大,且不同交錯角下f差別明顯,90°時f最大,PEC值隨錯位角的變化而呈現(xiàn)出復雜的變化規(guī)律,總體來說,60°的錯位角對應的綜合性能最好。湍流條件下,不同交錯角的交替軸扭帶的換熱差異不明顯,所以對窄邊扭帶和中空扭帶在湍流條件下進行了數(shù)值模擬,考察了換熱特性、阻力特性及綜合性能,并用速度場與溫度場進行了分析。通過計算結果可知:窄邊扭帶的寬度越大,換熱越好,阻力也越大,但綜合性能依然越好;中空扭帶的中空尺寸在較小時換熱基本一致,較大時換熱削弱,中空尺寸越大,阻力越小,綜合性能也越好;傳統(tǒng)扭帶的換熱性能及綜合性能始終優(yōu)于窄邊扭帶和中空扭帶。最后,還對湍流條件下管內內置不同結構形式的錐形環(huán)進行了數(shù)值模擬,發(fā)現(xiàn)固定錐形環(huán)小端端徑,環(huán)大端與管壁間間隙越小換熱越好;固定錐形環(huán)端徑比,對于收縮環(huán)環(huán)大端與管壁間間隙越小換熱越好,對于擴張環(huán)環(huán)大端與管壁間間隙適當?shù)脑龃蠓炊鴷䦶娀瘋鳠?擴張環(huán)與收縮環(huán)相比,在小間隙下阻力大很多,大間隙下阻力反而略小;擴張環(huán)的綜合性能始終優(yōu)于收縮環(huán)。
[Abstract]:Tube heat transfer enhancement technology is one of the common energy saving technology industry, widely used in energy, chemical, electronics, medicine, material and other fields. Therefore, the development of new technology of heat transfer enhancement, improve the heat exchange efficiency of the device has an important role for the development of energy and economy. This paper based on the study twist the narrow side, the design of alternating narrow shaft twisted tape, alternating narrow and twisting with the hollow shaft shaft wall hollow alternating twisted tape, and the pipe built-in above form twisted tape under laminar flow conditions were simulated. The results show that: for the narrow band and alternating axial torsion alternating narrow shaft the edge of the hollow twisted tape, in low Re, Nu with the increase of dislocation angle twisted tape increases, while the Re is high, the dislocation between the different angle difference is very small, the difference between F changes with the dislocation angle is small, the maximum PEC corresponds to 90 degrees angle. For alternating axis wall hollow twisted tape. 60 Under the angle of Nu degrees, and different stagger angle f was 90 degrees F maximum, PEC value changes with the dislocation angle shows the variation of the complex, in general, the comprehensive performance of misalignment angles of 60 DEG corresponding best. Turbulent flow condition, different stagger angle alternating axial thermal difference for the twisted tape is not obvious, so the narrow side twisted tape and hollow twisted tape under turbulent flow conditions was simulated and investigated the heat transfer characteristics, resistance characteristics and comprehensive performance, and was analyzed with the velocity field and temperature field. The calculation results indicate that: the narrow width of the twisted tape, change the thermal resistance is bigger, better, but still better comprehensive performance; hollow twisted hollow dimension is on the small heat exchanger is basically the same, large heat weakened, the hollow size is larger, the smaller resistance, comprehensive performance is better; the traditional twisted strip with the heat transfer performance and comprehensive performance is always better than the narrow side of the twisted tape The hollow and twisted tape. Finally, the conical ring pipe built-in with different structures under turbulent flow conditions were simulated, found the small end of the tapered end ring diameter, outer ring between the pipe walls and the smaller the gap the better heat transfer; the fixed cone ring end diameter ratio, the contraction between the pipe walls and the ring end gap the smaller the better heat transfer, expansion of the ring and the big end of wall clearance between the appropriate increase but will strengthen heat transfer; compared with expanding ring and shrinkage ring, in the small gap resistance large, large gap resistance but smaller; the comprehensive performance of the expanding ring is always better than the contractile ring.

【學位授予單位】：華中科技大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TK124

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本文編號：1380991