具45°交錯排列肋條U型銳轉靜止管道流場之數值模擬

Numerical Simulation of Flowfields in a Stationary Two-Pass Duct with Staggered Rounded Ribs Skewed 45-deg to the Flow

10.6124/TAASRC.200512_37(4).05

李宜宸(Yi-Chen Li)；劉通敏(Tong-Miin Liou)；戴昌賢(Chang-Hsien Tai)；黃柏文(Po-Wen Hwang)

45°交錯式排列 ； U型銳轉管道 ； 大渦數值模擬 ； 預調法 ； 45-deg staggered ； Two-pass duct ； Large-eddy simulation ； Preconditioning

中國航空太空學會學刊

37卷4期（2005 / 12 / 01）

325 - 332

繁體中文

本文嘗試以大渦數值模擬探討具45°交錯式排列肋條之U型銳轉管道流場特性。數值計算採用有限體積法配合預調法(Preconditioning method)來求解可壓縮Navier-Stokes方程式以模擬低雷諾數(Re=10000)之流場，式中時間項採用顯式三點向後差分法來進行離散，而對流項的處理則使用AUSMDV，並應用Van Leer所提出的Kappa法求解網格介面左右兩側流體性質，此外爲了防止數值震盪之發生，則搭配minmod限制子來監控變數的變化與提高空間精度爲二階，而擴散項的求解則採用中央差分法。計算結果發現模擬所得之管道中心線壓力分佈與實驗量測結果相當一致，且壓力等值線分佈與前人數值模擬結果趨勢相同；此外本文首度發現所檢視之流場其演化發展成空間週期全展所需之節距數與通道入口速度分佈無關，此一觀察甚具參考價值。

Large-eddy simulation has been applied to study fluid flow in a stationary two-pass duct with 45-deg staggered ribs. A density-based solver based on a cell-centered finite-volume method in conjunction with the preconditioning method was used to solve the ensemble-averaged Navier-Stokes equations under a Reynolds number of 10000. The time-integration scheme employed a three point backward difference method. In the space discretization, the diffusion and convection term were respectively discretized by using the second order center flux-difference splitting and the AUSMDV. The flow properties on the two sides of the cell's interface were determined by the van Leer's Kappa scheme. A minmod limiter was used to prevent numerical oscillation and raise the spatial accuracy to second-order. It is found that the predicted centerline wall-pressure distributions on the leading and trailing walls agree well with measured results. The computed pressure contours are qualitatively similar to those reported by previous researchers although the duct geometry and parameter range are somewhat different between the two studies. In addition, the critical pitch index beyond which the examined flow attains fully developed flow condition is found to be practically independent of the pass inlet velocity profile. This observation is reported for the first time and believed to provide a useful reference for CFD in this area.