CAJ | 학술논문

采用数值方法对弓形横截面螺旋半管夹套内流体的湍流流动与换热特性进行了研究.基于正交螺旋坐标系给出了夹套内换热流体充分发展的湍流流场与温度场分布.研究了雷诺数Re和无量纲曲率δ对流动阻力 fRe及壁面平均换热努塞尔数 Num的影响.结果表明:充分发展湍流条件下,弓形截面螺旋半管夹套的横截面上,平均轴向速度的最大值位置靠近弯曲的外壁侧;二次流为旋转方向相反的两涡结构.相同换热面积时,在0.058≤δ≤0.12,6000≤Re≤12000的范围内,弓形截面夹套的流动阻力fRe是半圆形截面夹套的0.794~0.947倍,平均努塞尔数Num为0.86~0.98倍.
채용수치방법대궁형횡절면라선반관협투내류체적단류류동여환열특성진행료연구.기우정교라선좌표계급출료협투내환열류체충분발전적단류류장여온도장분포.연구료뢰낙수Re화무량강곡솔δ대류동조력 fRe급벽면평균환열노새이수 Num적영향.결과표명:충분발전단류조건하,궁형절면라선반관협투적횡절면상,평균축향속도적최대치위치고근만곡적외벽측;이차류위선전방향상반적량와결구.상동환열면적시,재0.058≤δ≤0.12,6000≤Re≤12000적범위내,궁형절면협투적류동조력fRe시반원형절면협투적0.794~0.947배,평균노새이수Num위0.86~0.98배.
Numerical study on fluid turbulent flow and heat transfer characteristic in the half-pipe coiled jacket with arch cross section was carried out. Based on the orthogonal helical coordinate, the developed flow and temperature fields distributions were displayed. Effect of Reynolds number Re and curvature ratio δ on flow resistance fRe and average Nusselt number Num were researched. Results show that, under the fully developed turbulent flow condition, the position of the maximum axial velocity is near the outer curved wall on the arch cross section of half-pipe coiled jacket. The secondary flow patterns are two contrary rotating vortexes. With the same heat transfer surface, fRe of the half-pipe coiled jacket with arch cross section is 0.794~0.947 times and Num is 0.86~0.98 times those of the jacket with semi-circular cross section in the range of 0.058≤δ≤0.12 and 6 000≤Re≤12 000.