Transcript – A Thermally Actuated Microvalve for Smart Irrigation in Precision Agriculture Applications

Hi Everyone, I am Alaba Bamido, a PhD student in Mechanical Engineering. The title of my research poster is “A Thermally Actuated Microvalve for Smart Irrigation in a Precision Agriculture Application”. This work was presented at the American Society of Mechanical Engineers Summer Heat Transfer Conference of 2020. It is currently impossible to control irrigation-water application at the level of a single plant. Even with drip irrigation, in which emitters could be placed on a plant-by-plant basis, there is still no way to control the amount of water emitted to the individual needs of the plant. If such a capability were available on farms, the result would be a step change in precision agriculture, such that the output of every plant in a farm field could be optimized. This is the motivation of my research.

The aim is to develop and test a microfluidic system that could be controlled to deliver the needed amount of water to individual plants in a large field. To develop such a system, it is essential to develop microvalves that regulate the flow of water with high precision in real time, as well as an electronic actuation system for an array of microvalves in a farm field.

My design is a normally open thermally actuated microvalve. The design has two layers- a flow layer where the water flows and a control layer which controls the actuation of the microvalve. The microvalve was manufactured by soft-lithography and the microvalve was made with soft polymer called Polydimethylsiloxane or PDMS. Two designs were developed: Design 1 has air as the actuation medium and Design 2 has Phase Change Material as the actuation medium.

A simple experimental setup was used to determine the performance of the microvalve. The microvalve was heated and the reduction in flow rate was determined. A prototype electronic actuation system was also developed. Simple and low cost manufacturing produced a functional prototype microvalve. For Design 1, the actuation reduced the normally open flow rate by 60% while for Design 2, the actuation reduced the normally open flow rate by 40%.

As a future direction, we are going to be performing computer modelling to improve on the design, experimental validation, system assembly and testing. I want to thank the faculty and staff in my lab as well as the T3 grant committee for making this research a success. Thank you!