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Experimental Study of High Weber Number Impact of Methoxy-Nonafluorobutane C4F9OCH3 (HFE-7100) and n-Heptane Droplets on a Heated Solid Surface.


pdf icon Experimental Study of High Weber Number Impact of Methoxy-Nonafluorobutane C4F9OCH3 (HFE-7100) and n-Heptane Droplets on a Heated Solid Surface. (778 K)
Manzello, S. L.; Yang, J. C.

International Journal of Heat and Mass Transfer, Vol. 45, No. 19, 3961-3971, September 2002.

Keywords:

droplets; fire suppression

Abstract:

An experimental study is presented for methoxy-nonafluorobutane (C4F9OCH3, HFE-7100) droplet impingement on a heated solid surface. The impaction process was recorded using a high-speed digital camera at 1000 frames per second. The initial droplet diameter was fixed at 1.7 mm 0.1 mm, and all experiments were performed in atmospheric air. The impact velocity was fixed at 2.0 m/s thus defining an impact Weber number of 750. The impacted solid surface was made of polished stainless steel. The droplet evaporation lifetime was measured as a function of temperature to determine the Leidenfrost temperature of HFE-7100. The temperature of the stainless steel surface was varied from 20 C to above the Leidenfrost temperature of HFE-7100. Experiments were also performed using n-heptane to investigate whether the collision dynamics were similar if the impact Weber number was matched to HFE-7100 and collision considered within the same boiling regimes as HFE-7100. While the collision dynamics were qualitatively similar, the evolution of liquid film diameter with time was different. Thus, the evolution of liquid film diameter with time must be measured for a particular fluid. Existing models used to describe the evolution of liquid film diameter with time were found to be inadequate to describe HFE-7100 and n-heptane impact.