Additive manufacturing of scalable jet impingement and radial taper enhancements for improved flow boiling performance

Abstract

Additive manufacturing (AM) offers a unique route to improve flow boiling heat transfer by enabling the fabrication of complex fluidic devices. In this study, two types of advanced jet impingement designs were additively manufactured and tested in subcooled flow boiling of DI water with 20 °C of subcooling. The first design was an in-line extended nozzle jet impingement manifold with nozzles off angle to the flow direction that extend towards the heated surface in order to decrease pressure drop and reduce viscous dissipation. The influence of jet velocity was explored and the optimal 3 nozzle design achieved a critical heat flux (CHF) of 191 W/cm2 and heat transfer coefficient (HTC) of 42.1 kW/m2K at a pressure drop of 3.4 kPa. This represents a 78% increase in CHF and 64% increase in HTC compared to open flow conditions. Following this, a second more complex design was created combining jet impingement, tapered flow paths, radial flow, and intricate fluidic routing to further improve heat transfer. This complex design would be extremely difficult to manufacture without additive techniques and resulted in a CHF of 375 W/cm2 and HTC of 74.2 W/m2K at a pressure drop of 3.5 kPa at a flow rate of 300 mL/min. This represented a 250% and 189% increase in CHF and HTC respectively over open channel flow conditions at a low pressure drop. These designs are easily scalable, and represent a new class of “on surface” flow boiling jet impingement enhancement techniques enabled through the use of additive manufacturing of polymeric materials.