Experimental investigation on heat transfer enhancement from an inclined heated cylinder with constant heat input power in infrasonic pulsating flows

• An empirical equation of heat transfer for an inclined cylinder in pulsating flows was developed.
• The heat transfer enhancement factor decreases with the Strouhal number, and increases in trend with the inclination angle.
• There is a critical frequency resulting in different trends of the heat transfer enhancement factor with the Reynolds number.

Experiments were carried out to study the heat transfer performance of an inclined heated cylinder in pulsating flows. An empirical equation was developed that correlates the heat transfer enhancement factor to the infrasonic pulsating frequency (f = 6–20 Hz), Reynolds number (Re = 71–282), pressure amplitude (prms = 9–22 Pa), and inclination angle (θ = 0–90°). The heat transfer enhancement factor was found to decrease with the Strouhal number, and increase in trend with the inclination angle. In addition, a critical frequency (fcr ≈ 14–18 Hz) was observed, below which the heat transfer enhancement factor decreases in trend with the Reynolds number, but it increases in trend with the Reynolds number when the frequency is above the critical frequency.