Effects of Flow Pulsation on Forced Convection in a Channel Containing Regularly Spaced Nonconducting Fins

Abstract

The effects of pulsating flow on forced convection in a rectangular channel containing a series of regularly spaced, nonconducting inserts were investigated experimentally. Based on the experimental data, a correlation equation was developed. The steady-flow Reynolds number Re in the laminar range, Re < 1200, was examined. The Prandtl number of the working fluid Pr = 15 and the oscillation was generated using low-frequency oscillation at f < 50 Hz and amplitude A < 1 mm. The energy dissipation as a result of applied oscillation was determined by phase-resolved measurements of pressure difference and liquid displacement. The system shows improved convective heat transfer towards a low Reynolds number. At a higher Reynolds number, the influence of the oscillation diminished and the flow approaches a steady finned flow. The predictions of the developed correlation equation are in good agreement with the experimental data. The calculated power input due to oscillation is comparatively low and decreases towards increasing net flow rates where the oscillating flow has a diminishing effect.

Residence Time Distribution of Steady and Pulsed Flow in a Parallel‐Plate Channel with Staggered Fins

“…In addition, they cause curved shear layers, flow deflection, and impingement against the opposite wall. However, higher streamwise pressure drops are associated with the flow in such a system [1,2,[4][5][6]. The flow over the fins is similar to the geometry of shell and tube heat exchangers and of corrugated channels [7].…”

“…In addition, the use of long channels is feasible and system fouling can be reduced due to increased wall shear and eddy formation. Several studies have shown that oscillating flow in tubes or parallel ducts with corrugated or finned walls significantly enhances heat and mass transfer in the laminar flow regime [6,[11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. This influence has been attributed to substantial fluid mixing resulting from the system configuration.…”