## Scientific Data in Subproject B1

## Description

**General Informations on the Datasets**

The data are an excerpt of the experimental and numerical investigation in Subproject B1 concerning the evaporation of freely suspended supercooled water droplets at varying relative humidities and ambient temperatures. The data is suitable for the validation of numerical codes and experiments. Further information about the experimental setup can be found in: http://dx.doi.org/10.1016/j.icheatmasstransfer.2016.08.005

**Experimental setup and results**

In the experiment, single water droplets are optically levitated with a focused laser (λ=532nm). The uploaded data contains the experiments at the ambient temperature T=5°C for varying relative humidity. Each experiment is stored in a folder named considering the ambient conditions, e.g. „Temp_-10_RH_47“. A CCD camera (2048 pixel) records the elastically scattered light for about 12 s, which equals 60.000 lines. The measurement data and the evaluated data for each measurement is stored in a Matlab file, containing the following variables:

abstaende_grad |
Mean distance between two maxima in degree at time t |

angle |
Observation angle of camera |

beta |
Evaporation rate in µm²/s |

D |
Calculated diameter at time t |

D0 |
Extrapolated diameter at time t=0s |

D_D0 |
Non dimensional diameter D/D |

ende_corr |
End of correlation window to derive the evporation rate β |

filterWindowSize |
Window with for filter |

ImageMatrix |
Raw data from CCD Kamera |

n |
Calculated real refractive index, see publication |

p |
Ambient pressure in Pa |

phi_inf |
Relative humidity |

start_corr |
Begin of correlation window to derive the evaporation rate β |

t |
Time at which the camera recorded a line |

t_D0 |
Time t divided by initial diameter, t/D |

T_inf |
Ambient temperature |

T_wetbulb |
Calculated wet-bulb temperature in K |

The folder position includes the measurement data from the oscilloscope for each measurement. Channel 1 (CH1) is the position of the droplet in Volt and channel 2 (CH2) corresponds to the intensity of the scattered light under an angle of 90° in Volt. CH_Time is the time base of the oscilloscope.

**Numerical setup and results**

The simulation is performed on a Cartesian, three dimensional grid. The grid resolution is 512 x 256 x 256 cells. The setup for the simulation is an inflow on the left and an outflow on the right hand side. Free slip conditions are used on all lateral boundaries. An additional damping zone avoids undesired back flow. The initial water droplet is levitated in a nitrogen atmosphere and has a diameter of 50 µm. The ambient temperature is 268.15 K, the droplet is initialized with the wet bulb temperature which is 263.15 K. The ambient pressure is 0.965 bar. The inflow velocity is constant and has a value of 0.5 cm/s. The initial humidity of the atmosphere is 0%.