Drop impact cooling enhancement on nano-textured surfaces. Part I: Theory and results of the ground (1 g) experiments

The present work consists of two parts. Part I covered in this article is devoted to the experimental setup built as a prototype of the setup for parabolic flights and tested in the earth experiments at 1 g. This part encompasses the sample (nanofiber mat) preparation by electrospinning, sensitization and electroplating, as well as the development of the drop-on-demand device for drop cooling. It also details the methodology of the heat flux measurements, in particular, an in-depth exploration of the non-trivial interplay between the heater operation and drop cooling. The article also contains theoretical foundations developed in the present work for the measurement methods used. The results of the earth experiments in Part I encompass the experiments with a single needle producing drop trains or jets with water or Fluorinert fluid FC-7300. The article also contains the experimental results obtained with two-needle system used for droplet generation, as well as the discussion of all the results obtained.