City Research Online

Abstract

A combined experimental and computational investigation of micrometric diesel droplets impacting on a heated aluminium substrate is presented. Dual view high-speed imaging has been employed to visualize the evolution of the impact process at various conditions. The parameters investigated include wall-surface temperature ranging from 140 to 400°C, impact Weber and Reynolds numbers of 19–490 and 141–827, respectively, and ambient pressure of 1 and 2 bar. Six possible post-impact regimes were identified, termed as Stick, Splash, Partial-Rebound, Rebound, Breakup-Rebound and Breakup-Stick, and plotted on the We-T map. Additionally, the temporal variation of the apparent dynamic contact angle and spreading factor have been determined as a function of the impact Weber number and surface temperature. Numerical simulations have also been performed using a two-phase flow model with interface capturing, phase-change and variable physical properties. Increased surface temperature resulted to increased maximum spreading diameter and induced quicker and stronger recoiling behaviour, mostly attributed to the change of liquid viscosity.

Publication Type:	Article
Additional Information:	© 2018 The Authors. Published by the Royal Society. All rights reserved.
Publisher Keywords:	Diesel, droplet, hot surface, Leidenfrost, impingement, CFD
Subjects:	T Technology > TJ Mechanical engineering and machinery T Technology > TL Motor vehicles. Aeronautics. Astronautics
Departments:	School of Science & Technology > Department of Engineering
SWORD Depositor:	Symplectic Administrator

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