A Numerical Study of the Mixing Phenomena of Multi-Jets in the Sudden-Expansion Dump Sequential Burner

• Main Authors: CHIN-HSIEN YEN, 顏欽賢
• Other Authors: none
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/e32wre

碩士 === 逢甲大學 === 機械工程學所 === 90 === Abstract In this study, a computational fluid dynamics（CFD）code, PHOENICS, is used to simulate the flowfield of the transverse jets with angle of inclination impacting each other on the three-dimensional confined cross flow. It adopts the two-equations turbulence model and the control-volume integration formula for finite difference and SIMPLEST algorithm to find more flowfield morphological characteristic of the various mixing configuration of the transverse jets. In the different jets configuration, the velocity vector, temperature, pressure,and the situation of mixing between the cross flow and opposed jets will be studied one by one. For S/D=8 and S/D=6 case，the results show that the angle of inclination of transverse jets between and would produce the eddies which they are similar to form of 8. Because of these eddies have very strong efficacy and stay in the flowfield for a long time, the overall mixing rate will be nice. When the angle of inclination between and , the angle of jets slope very much and the jets fluid almost collect on the up-plane and down-plane in every kinds of jets configuration.The heat transfer is much worse between jets flow and cross flow at the center of duct, so the overall mixing rate decrease very much. In terms of the momentum flux ratio up to J=20, we can observe the jets mixing rate the same as J =30 at the downstream location 0f X/H=2.We can choose the low momentum flux ratio to economize energy. In cases of small spacing （S/D=4）overall mixing rate and pressure much higher than large spacing（S/D=8）. Keywords：sequential burner, momentum flux ratio, mixing rate, angle 0f inclination of transverse jets