The influence of wall superheat and drop impact parameters on heat transfer during drop impact on a hot wall

In the last decades numerous experimental and numerical studies have been carried out addressing the heat transfer during drop impact on a hot wall. This phenomena occurs in variety of applications such as fuel injection into combustion engines and spray cooling. To obtain a detailed understanding of the heat and mass transfer mechanisms during drop impact, an experimental study is essential. Embedded on this background, the main objective of this study is to experimentally investigate the influence of wall superheat as well as drop impact size and velocity on heat transfer during drop impact on a hot wall. The experimental setup consists of a temperature-controlled test cell, which is maintained under the saturated condition of working fluid FC-72. A drop is generated inside the cell thanks to a syringe pump. This experiment is making use of high spatial and temporal resolution thermography and shadowgraphy techniques to measure the temperature field as well as to visualize the drop hydrodynamics. Various drop sizes and impact velocities can be achieved through varying the needle size and height, respectively. Distinctive wall superheat is obtained by passing various current through the heater. The experimental results are validated with an existing model.