Effect of Longitudinal Spacing on The Flow and Heat Transfer for Staggered Drop-shaped Tubes Bundle in Cross-flow

A numerical study has been conducted to investigate the effect of the longitudinal spacing on the flow and heat transfer characteristics for a staggered drop-shaped tubes bundle at zero angle of attack in crossflow. The study is performed for the Reynolds number Re= 3.18x103 ~ 3.25x104, while the longitudinal spacing SL is 37 and 46.25 mm. A mathematical and numerical model in software package ANSYS FLUENT has been developed for numerical evaluation of heat transfer and flow field of a bundle of drop-shaped tubes, taking into account the strain caused by different pressures inside and outside the tubes. Correlations of the average Nusselt number Nu and a friction factor f in terms of Re and SL for the studied bundle was presented. The result of the present study indicates the superior thermal-hydraulic performance of the drop-shaped tube bundles with a longitudinal spacing of 37 mm over that with a longitudinal spacing of 46.25mm.

Drop-shaped tube, heat transfer, friction factor, Organic Rankine Cycle, longitudinal Spacing, numerical investigation

Volume 21, issue 1, 2020 year

Влияние продольного расстояния на гидродинамические характеристики и теплообмен при поперечном обтекании шахматного пучка труб каплевидной формы

Проведено численное исследование для исследования влияния продольного расстояния на характеристики потока и теплообмена шахматного пучка каплевидной формы при нулевом угле атаки в поперечном потоке. Исследование выполнено для числа Рейнольдса
Re= 3,18х103 ~ 3,25х104 и для продольного расстояния SL составляет 37 и 46,25 мм. Представлен анализ литературы. Разработана математическая и численная модель для расчета теплообмена и поля потока пучка каплевидных труб с помощью пакета ANSYS FLUENT с учетом напряженно-деформированного состояния труб. Представлены корреляции, позволяющие определить средние по рассмотренному пучку каплевидных труб числа Нуссельта Nu и коэффициента трения f в зависимости от Re и SL. Результаты настоящего исследования показывают, что тепло-гидравлические характеристики пучка труб с продольным шагами 37 мм лучше, чем у продольного шага 46,25 мм. Полученные данные свидетельствуют о существенно более высоких тепло-гидравлических характеристиках каплевидных труб по сравнению с трубами круглого поперечного сечения.

Каплевидные трубы, теплообмен, коэффициент трения, Органический цикл Ренкина, продольное расстояние, численное исследование

Volume 21, issue 1, 2020 year

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