Enhancement of Heat Transfer by Ultrasound: Review and Recent Advances

Table 5

Summary of numerical researches on convection increase by ultrasound.

Reference	Description of the study	Frequency, power, intensity	Best and/or interesting result obtained
Aktas et al. [81]	Shallow enclosure, vibrating vertical side wall, acoustic streaming	20 kHz and 25 kHz	After 5 ms, ℎ/ℎUS≈40/320 at 20 kHz, ΔT = 10 K
Cai et al. [79]	Square enclosure—hot bottom, natural convection, acoustic cavitation, ultrasonic beam from the centre	18 kHz	Field synergy principle analysis, 25% increase in ℎ at the centre
Lin and Farouk [13]	Gas-filled square enclosure vibrating side-wall, top-side heated	20 kHz	Heat transfer enhanced with streaming flow velocity (maximum at the middle of the bottom wall)
Wan and Kuznetsov [80]	Acoustic streaming in a gap (0.1–2 mm) between two horizontal beams, the lower vibrating	160 Hz; (no ultrasound)	1% increase in Nusselt number for constant heat flux case of the upper beam
Wan and Kuznetsov [14]	Air channel composed of two parallel beams, upper beam vibrating	21 kHz	h from 0.9 to 82 W m^−2 K^−1 at constant heat flux, decreasing with channel width