Heat Transfer Effectiveness of Saturated Drops in the Nonwetting Regime Impinging on a Heated Surface Heat Transfer Effectiveness of Saturated Drops in the Nonwetting Regime Impinging on a Heated Surface

A theoretical analysis of impact dynamics and heat transfer is performed on single, deformable, saturated drops to determine heat transfer effectiveness, using idealized shapes to model the deformation. Numerical results are obtained for various liquid drops in the nonwetting regime with diameters of 0.22 to 4.0 mm, wall superheat temperatures of 200 to 600 K and Weber numbers of 12.3 to 50. The drop heat transfer effectiveness is expressed in the form of a correlation equation of four dimensionless parameters, including Weber, Bond and Prandtl numbers, and a new parameter which can be interpreted as the ratio of the inertial force induced by the accelerating vapor flow inside the superheated vapor layer to the elastic restitution force of the drop itself due to surface tension forces. The correlation equation agrees well with the existing experimental data in the absence of air entrainment and drop subcooling.

A theoretical analysis of impact dynamics and heat transfer is performed on single, deformable, saturated drops to determine heat transfer effectiveness, using idealized shapes to model the deformation. Numerical results are obtained for various liquid drops in the nonwetting regime with diameters of 0.22 to 4.0 mm, wall superheat temperatures of 200 to 600 K and Weber numbers of 12.3 to 50. The drop heat transfer effectiveness is expressed in the form of a correlation equation of four dimensionless parameters, including Weber, Bond and Prandtl numbers, and a new parameter which can be interpreted as the ratio of the inertial force induced by the accelerating vapor flow inside the superheated vapor layer to the elastic restitution force of the drop itself due to surface tension forces. The correlation equation agrees well with the existing experimental data in the absence of air entrainment and drop subcooling.