Experimental study on optimal spray parameters of piezoelectric atomizer based spray cooling

Abstract

Piezoelectric atomizer could enhance heat transfer of spray cooling at low flow rate through improved atomization of liquid droplets. To optimize the heat transfer performance of piezoelectric atomizer based spray cooling, a novel piezoelectric atomizer was designed in this paper. The piezoelectric atomizer was composed of two piezoelectric ceramic films (110kHz) and a stainless steel micropore disk with different outlet diameters of 5m, 7m, 9m, 20m and 25m (corresponding flow rates of 0.5 mL/min, 1.0 mL/min, 3.8-5.0 mL/min, 11.0-16.0 mL/min and 20.0-29.0 mL/min, respectively). The effects of micropore outlet diameter, volumetric flow rate and spray height on surface temperature distribution, heat flux and the spray cooling efficiency were studied. It was found that the volumetric flow rate increased with the increase of micropore outlet diameter. As the flow rate increased, the heat flux increased but the spray cooling efficiency decreased as a sacrifice. The correlation between spray cooling efficiency/heat flux and flow rate (range from 0.5 mL/min to 29.0 mL/min) of all atomizers could be generalized into one exponential decay/growth curve. An optimal diameter of 9m could achieve high heat flux of 123.8 W/cm 2 at a relatively low volumetric flow rate of 5.0 mL/min, and the corresponding spray cooling efficiency was as high as 53.8%. For each atomizer, there was an optimal spray height which differs with the micropore outlet diameter.

AM of three‐dimensional spongy microstructures for a piezoelectric sprayer

“…In addition, the decrement of the rate of 0.55 ml/min (at 105.5 kHz) and 0.53 ml/min (at 110.8 kHz) occurred due to significant loss of pumping pressure within the PA cavity. It showed the maximum of volumetric rate around 1 ml/min at the resonant frequency of −107 kHz, agreeing with those data measured for small diameters (5-7 µm) of nozzles [35]. The difference between the volumetric rates of present and previous work was attributed to the size, morphology, and properties of the material that affect the fluidic flow through the nozzles.…”

Spray Impingement Cooling: The State of the Art

“…The same conclusion was made when comparing the cooling performance of droplet train and jet impingement on flowing film that cools the hot surface [75]. Through piezoelectric nozzles more groups of jet flow were generated and broke up to droplet train for cooling the hot surface [76], and the maximum heat flux reaches~ 170 W/cm 2 with the nozzle diameter of 25 μm. However, unclear impact dynamics and its relation to local cooling need the further study.…”

Spray Cooling on Enhanced Surfaces: A Review of the Progress and Mechanisms

“…On the other hand, to meet the heat dissipation requirements of next-generation power electronics and devices, further development of advanced spray cooling is urgently needed. There are multiple ways to improve the spray cooling performance, including selection and alteration of the working fluid [39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57], optimization of spray parameters [58][59][60][61][62] or systems [17,[63][64][65][66][67][68][69][70][71][72][73][74][75][76], and surface engineering. The first two methods are based on the fluid side, which is limited in affecting liquid-wall interactions.…”