Three-Dimensional Structure of Turbulent Flow in Mixing T-junction

Abstract

Experimental results on the turbulent mixing of hot and cold airflows in a T-junction are reported, which simulates the HVAC unit used in an automobile air conditioning system. Experiments are conducted keeping Reynolds number and temperature of the main flow at 2.5 × 10 4 and 12• C, respectively, and the velocity of the branch flow (60 • C) is changed for three velocity ratios of 0.5, 1 and 2. The flow from the branch is separated at the edge of the T-junction and forms a large separation bubble. Longitudinal vortices are formed around this separation bubble, thus the flow field has a three-dimensional structure. In spite of such a complex flow field, the mean temperature in the thermal mixing layer shows quite uniform distributions in the spanwise direction, and the strong turbulence produced around the separation bubble does not work effectively to the thermal mixing of hot and cold airflows.

Investigation on the flow characteristics inside an automotive HVAC system with varying ventilation mode

“…On the other hand, Yoon and Lee (2003) investigated experimentally the ventilation flow inside a 1/10-scale vehicle model. Hirota et al (2006) investigated turbulent air mixing in the T-junction of the HVAC system, while James et al (2004) developed a cylindrical HVAC case.…”

Effect of corner shape on pressure loss and heat transfer of turbulent channel flow with T-junction

“…© 2014 The Japan Society of Mechanical Engineers [DOI: 10.1299/transjsme.2014fe00 ] 89 ．さらに，分岐角部の曲面に関連する研究として，山口らは分岐後の壁面せん 断応力に及ぼす影響(山口他， 1994)， 池田らは分岐損失とキャビテーションに及ぼす影響について調査している(池 田他，1987)． しかしながら，分岐を伴う流れに関しては，これまで円管に対してなされた研究が多く，チャネル流れに関す る研究例は少ない．また，T 字の分岐・合流管において本管側の伝熱特性を調査した研究は存在するものの (深 澤，佐野，2006; Hirota, et. al., 2006; Contours of normal velocity V for Q 12 =0.4, and H 12 =0.5, 1.0 and 1.5.…”