Fog Density Measurment<
Project Description<
My ongoing PhD thesis is about understanding fog droplets motion around obstacles and more specifically trying to use these understandings to improve fog harvester. Therefore a test bench was built in the lab that allows one to simulate real conditions and test their prototypes.
It is composed of a fog generator, a laminar air flow generator, two concentric plastic cylinders and two weighing scales. The fog created by the generator is carried away by the laminar air flow and passes around a hanging obstacle. The top weighing scale measures the mass of the fog water deposited on the obstacle while the bottom one measures the mass of the water drained and hence harvested.
The interseting datas we extract from our measurements require the value of the supplied water mass rate. However, our setup does not allow us to measure it directly therefore we estimate by measuring the water tank mass before and after our measurements.
A nice way to measure the provided water mass rate would be to use light scattering by either measuring how much light is transmitted through the fog or directly how much light is scattered. If we even manage to measure the directions at which the light is scattered, it could give informations about droplets sizes distribution.
Theory<
When light interracts with a droplets, there is a probability that it scatters. By installing a laser going through the fog and a photosensor at a certain angle with the laser direction, one could measure a signal due to the scattering. This signal would be more intense if the fog is more dense.
To do : detail theory
Experimental Setup<
Phototransistor test<
To do : resume week 9 assignment