Project Details
[Return to Previous Page]Handheld 3D Printed Water Pump
Company: Mechatronics Research Lab
Major(s):
Primary: ME
Secondary: ESC
Optional: ED
Non-Disclosure Agreement: NO
Intellectual Property: NO
Background: Additive manufacturing has the potential to revolutionize the design of mechanical components for aerospace applications. The incorporation of fluids inside metal parts can add damping to the stiffness and strength. The concept shown in the figure above includes additively manufactured fluid chambers and inertia tracks that can be tuned to provide the desired static and dynamic performance in the challenging rotorcraft application. Designing and building these complex fluidlastic systems require a strong understanding of how to build chambers, pumping units, and inertia tracks inside structures. This project builds a handheld demonstrator that includes these elements to show how internal compliant structures in a solid part can move fluid as the part vibrates. Design: The deliverable for this capstone project is a polymer 3D-printed water pump. The pump has a beam-shaped monolithic design with internal functional fluidic components. The pump contains an upper and a lower chamber connected with a fluid track. The fluid track incorporates a one-way valve that facilitates unidirectional fluid flow and a flow control needle valve that controls flow volume. The pump incorporates external filling ports that enable the filling of the device with a fluid. The device needs to be filled such that no air bubbles are formed inside the chambers or the fluid track. Additionally, two handholds are incorporated at the ends of the beam that enable gripping the device for actuation. Working Principle: To pump the fluid, the device is bent, which causes elastic deformation in the upper and lower chamber walls, changing the chambers' volumes. This deformation results in a volumetric gradient between the upper and the lower chamber that drives the fluid through the fluid track. By bending the device back and forth, the one-way valves make the fluid go in a loop from the top chamber to the bottom and then back up to the top. This device also stiffens when the fluid track flow is restricted. When the device is bent, the pressure generated due to volume changes self-corrects the device’s deformation. This self-correction caused by restricted fluid flow makes the device much stiffer compared to when the fluid is allowed to flow through the fluid track. Analytical Modeling: Analytical modeling of the chamber walls has been undertaken to estimate the fluid flow. The volumetric gradient driving the fluid flow depends on the compliance of the chamber walls. The compliance of the chambers depends on three design parameters, wall geometry, wall thickness, and the constitutive material. Several possible chamber wall geometries that can be used to vary compliance. Euler-Bernoulli beam theory will be used to develop an analytical model that predicts the deflection of the chamber walls based on the design parameters being used. The deflection of the chamber walls will be used to estimate the volumetric gradient being produced between the chambers. By changing different design parameters, desired fluid flow can be achieved based on application requirements. The team will be provided with optimal chamber geometries for fabrication. Manufacturing: The water pump will be 3D printed using Fused Deposition Modelling (FDM) using a transparent polymer as the base material. The transparent material will allow for an easy demonstration of the pumping mechanism. Design for additive manufacturing (DfAM) principles need to be considered during the design of the device. For instance, geometric features with overhangs less than 45 degrees will require support structures that will be impossible to remove from the internal cavities thereby affecting their functionality. The device must be manufactured with no internal supports inside the top and bottom chamber and the fluid track. Fixtures for filling ports and needle valves should be additively manufactured into the device. This would enable easy installation and proper functions of the one-way needle valve and NPT fixtures required for filling the chambers. Finally, one-way valves will be incorporated in the two fluid tracks. Experimental testing: The device should be filled with water dyed with blue ink. A repeatable filling setup should be used to fill the device to make sure no air pockets are formed in the chambers or the fluid track. A bending force will be applied on the device using the handholds and the fluid actuation will be observed. The needle valve will then be closed to observe an increase in stiffness when the device is actuated. Project Challenges: • Designing the geometry of the chambers, fluid tracks, one-way valves, filling ports, and exterior structure with handholds. • Applying DfAM principles to design a component that can be manufactured without supports. • Creating a zero-bubble filling setup that can repeatably fill the component.