ライブラリ登録: Guest

ISBN: 978-1-56700-537-0

ISBN Online: 978-1-56700-538-7

ISSN Online: 2377-424X

International Heat Transfer Conference 17
August, 14-18, 2023, Cape Town, South Africa

EVAPORATION AND RESIDUE FORMATION OF DIMETHYL CARBONATE DROPLETS ON HOT WALLS

Get access (open in a dialog) DOI: 10.1615/IHTC17.130-10
10 pages

要約

When fuel is injected into a combustion chamber, spray impingement regularly results in the formation of liquid wall films. These films can have a long lifetime and contribute negatively to the emissions of the process. It is therefore of interest to investigate and, if possible, improve the evaporation behavior of these films. The evaporation and residue formation process is also influenced by previous events and the corresponding state of the wall surface. Therefore, in this work, a large number of individual droplets of dimethyl carbonate (DMC) are deposited one after the other on a hot plate with variable surface temperature. The droplets then evaporate under controlled boundary conditions. Both the droplet geometry with high temporal resolution and the mass of any residues formed are recorded. At wall temperatures below or at the saturation temperature of DMC, residues remain on the surface after the droplets have evaporated. As the number of droplets increases, the mass of residue increases as well, but approaches an upper limit as the test series progresses. The highest mass of residue is measured when the surface temperature is equal to the saturation temperature. Below the saturation temperature, the residues mix with the subsequent droplets to form a multicomponent fluid with different volatilities. As a result, the evaporation time of the individual droplets is prolonged, since diffusion of the volatile component to the liquid-gas interface is limited. Residues that form at the saturation temperature do not appear to be miscible with subsequent DMC droplets and do not affect the evaporation rate. The results indicate that when studying the evaporation behavior of films on hot walls, and their influence on coupled processes, the history of the wetted surface must also be considered.