An experimental study of local heat transfer of dimple vortex generator using transient liquid crystal thermography

作者：Li, Bo; Rao, Yu^*; Chen, Peng

来源：Journal of Engineering Thermophysics, 2015, 36(11): 2356-2360.

• Dimple
• Flowcharacteristics
• Local heat transfer
• Local heat transfer coefficient
• Local Nusselt number
• Thermal performance factors
• Thermography techniques
• Transient liquid crystals

An experimental study using a transient TLC thermography technique has been conducted on the flow frictioncharacteristics and local heat transfer performance in a channel with spherical/elliptical dimples. Height of the channel is 10 mm. The ratio of dimple depth to duct height is 0.2 and the ratio of print diameter to duct height is 1.0. Reynolds number, which is based on the hydraulic diameter, is tested in high range values from 8500 to 51000. The research shows that the Nusselt number of circular dimples'is 1.45~1.55 times that of smooth flat, with friction factor is 1.25~1.75 times that of smooth flat. However, the Nusselt number of elliptic dimples is 4%~15% lower than circular dimples'and friction factor is 5% higher. This study has obtained local heat transfer coefficients on the circular/elliptic dimple walls. The heat transfer coefficients on the latter part of dimples is higher than that on the front part. Theoverall thermal performance factor (Pf) of circular dimples is 14% higher compared with elliptic dimples.

• 出版日期2015
• 单位上海交通大学