Experimental study on inlet turbulent flow under ultrasonic vibration: Pressure drop and heat transfer enhancement

• Published in: Ultrasonics sonochemistry Vol. 51; pp. 151 - 159
• Main Authors: Amiri Delouei, A., Sajjadi, H., Mohebbi, R., Izadi, M.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-03-2019
• Subjects: Experimental study; Heat transfer enhancement; Pressure drop; Turbulent; Ultrasonic vibration; Heat transfer enhancement; Turbulent; Experimental study; Pressure drop; Ultrasonic vibration
• ISSN: 1350-4177; 1873-2828
• DOI: 10.1016/j.ultsonch.2018.10.032

•The effect of ultrasonic vibration is very low in turbulent flows.•At a constant power level, the effect of ultrasonic declines with the increase in Re.•Heat transfer enhancement reduces with the growth of flow rate and inlet temperature.•At higher temperatures, the influence of augmenting the ultrasonic power is lower.•The current results will be useful for designing vibrating heat exchangers.
This experimental study examines the impact of ultrasonic vibration on pressure drop and heat transfer enhancement of inlet turbulent flows. A stainless steel tube connected to an ultrasonic transducer and immersed in a constant temperature two-phase fluid was considered as the test section. Regarding the designed configuration, the ultrasonic transducer utilized had an acoustic frequency of 28 kHz and two different power levels of 75 W and 100 W. The experiments were conducted for different ultrasonic power levels, inlet temperatures, and flow rates. The accuracy of measurements was successfully validated via the existing empirical correlations. The results indicate that the effect of ultrasonic vibration on pressure drop and heat transfer enhancement diminishes with the growth of both Reynolds number and inlet temperature. Based on previously reported results on inlet flows with a laminar flow regime, the effect of ultrasonic vibration is very trivial in current turbulent inlet flows (up to 7.28% for heat convection enhancement). The results of the present study will be beneficial for future investigations on designing vibrating heat exchangers.