Control of evaporation of substances at high temperature

• Main Author: Wee, Jonathan Joseph YaoWei
• Other Authors: Huang Weimin
• Format: Final Year Project
• Language: English
• Published: 2018
• Subjects: DRNTU::Engineering; DRNTU::Engineering::Mechanical engineering::Fluid mechanics
• Online Access: http://hdl.handle.net/10356/75599
• Institution: Nanyang Technological University

In a tropical climate like Singapore’s, motorists entering their cars on a sweltering day are often overcome with the pungent scent of their vehicles’ perfumes. As the interior temperature of a vehicle increases due to the trapped warm air, liquids in such environments will naturally evaporate at a much higher rate than usual. Several means of tackling this issue such as vents to prevent evaporation requires the user to manually adjust mechanisms to vary the evaporation rates. Other self-regulation methods are over complicated, requiring the use of temperature sensors and motors which could add considerable cost to the product. A need for an affordable solution to self-regulate evaporation rates was needed. To create a reliable solution under a few cents meant that the working principle had to utilise the natural phenomenon of volume change due to the phase change of a material. A possible solution uses a silicone-wax mixture (SWM). Silicone, with its high permeability, allows for perfume particles to easily permeate through. Wax, having high expansion coefficient and forces, is suspended within a layer of silicone. As temperature rises, the embedded wax increases in volume and pushes against the surrounding silicone, causing the micro-channels of the silicone to be compressed or blocked. This restricts the flow of perfume through the membrane, essentially controlling the rate of its evaporation. The method used to determine evaporation is by measuring the change in mass. The relatively cheap solution has shown to reduce the evaporation rate by 20 percent when compared to a control sample. Furthermore, this silicon-wax layer can be applied atop existing products, reducing the impact to the current manufacturing process.