Fluidics | EPFL Graph Search

Fluidics, or fluidic logic, is the use of a fluid to perform analog or digital operations similar to those performed with electronics. The physical basis of fluidics is pneumatics and hydraulics, based on the theoretical foundation of fluid dynamics. The term fluidics is normally used when devices have no moving parts, so ordinary hydraulic components such as hydraulic cylinders and spool valves are not considered or referred to as fluidic devices. A jet of fluid can be deflected by a weaker jet striking it at the side. This provides nonlinear amplification, similar to the transistor used in electronic digital logic. It is used mostly in environments where electronic digital logic would be unreliable, as in systems exposed to high levels of electromagnetic interference or ionizing radiation. Nanotechnology considers fluidics as one of its instruments. In this domain, effects such as fluid–solid and fluid–fluid interface forces are often highly significant. Fluidics have also been

Thermal management of components for high energy physics experiments and space applications

Timothée Robert Sophus Frei

High-energy physics (HEP) experiments and space missions share a common challenge: thermal management in harsh environments. The severe constraints in both fields make cooling of electronic components a major design concern. This thesis aims to develop high thermal conductivity, radiation hard devices for thermal management in HEP and space application with the help of micro-technologies.Continuous advances in micro-engineering have opened the door to the development of smaller and more efficient cooling devices capable of handling increasing power densities with minimum mass and volume penalties. In this respect, previous works have focused on the use of microchannels etched in single crystal silicon (ScSi) wafers to circulate a cooling fluid. However, whilst this technique represents the state-of-the-art for thermal management of silicon detectors, it poses several challenges, particularly those associated with the fluidic interconnections, compatibility with high operating pressures and coverage of large areas. A cooling scheme relying on two independent fluidic loops is proposed to overcome these limitations. The two cooling loops, referred to as the primary and the secondary cooling loops (i.e. PCL and SCL respectively), are connected through thermal and mechanical interfaces but do not share any fluidic interface. Both circuits work together to remove heat and control the temperature of multiple electronic components. The SCL transfers the heat generated at the source to the PCL, which transports it further away and dissipates it to the environment.The present thesis investigates the use of micro-oscillating heat pipes (uOHPs) to implement the secondary cooling loops. These devices offer great potential, particularly if embedded in silicon substrates. However, a better understanding of the mechanisms responsible for their self-actuated, two-phase flow is essential to produce high performance devices which meet the stringent requirements of particle detectors and spacecraft. Two types of dual-diameter uOHPs were microfabricated: the first version used a glass wafer to close trenches etched in a silicon substrate, while an all-silicon construction was adopted in the second type. The thermocompressed interface used to bond the two silicon wafers yielded excellent pressure resistance. The thermal performance of the of uOHPs was studied for different working fluids, charging ratios, orientations, and heat inputs, taking advantage of the transparent cover in the glass devices to monitor the two-phase flow for the different conditions. The results revealed that the performance of the proposed uOHPs was orientation-independent. Furthermore, under certain conditions the equivalent thermal conductivity of acetone-charged devices exceeded that of an equivalent copper strip.Finally, an innovative technique for charging and sealing the micro-cooling heat pipes was developed. It offers a low-volume, small-footprint solution to enclose working fluids in the devices. The proposed technique, which relies on a compressed Indium preform to seal the inlet charging port, yield very good leak-tightness results.

EPFL2021

3D-Integration Of Printed Electrochemical Sensors In Pet Microfluidics For Biochemical Sensing

Angélique Martine Bionaz, Danick Briand, Silvia Demuru, Marc Olivier Joho, Peter Van der Wal

This paper presents a novel process for screen printed electrode fabrication, functionalization and integration in a polyethylene terephthalate (PET) fluidics system for electrochemical analysis. The innovative components utilized are: 1. 3D Through-Foil Vias (TFVs) for electrode connection, enabling simple liquid tight lamination of micro-fluidic channels; 2. Screen printed carbon and silver/silver chloride (Ag/AgCl) electrodes on 3D vias; and 3. PET fluidics with a fabrication process compatible with large-area manufacturing. A platform integrating an Ag/AgCl pseudo-reference and a glucose oxidase (GOx)-modified working electrode has been used for glucose sensing in the flexible fluidics system. Detection of small glucose concentrations between 100-400 mu M through Cyclic Voltammetry (CV) is shown. The sensor shows linear response and good sensitivity of similar to 0.8 mA/(mM cm(2)). By changing the electrode coatings, the same technology can potentially be used for detecting multiple analytes in biofluids.

IEEE2019

Wireless Electrohydrodynamic Actuators for Propulsion and Positioning of Miniaturized Floating Robots

Vito Cacucciolo, Yu Kuwajima

Autonomous soft robots require compact actuators generating large strokes and high forces. Electro-fluidic actuators are especially promising, they combine the advantages of electroactive polymers (low-power consumption, fast response, and electrical powering) with the versatility of fluidic systems (force/stroke amplification). EHD (electrohydrodynamic) actuators are electro-fluidic actuators whose motion results from charges being induced and accelerated in a liquid. They are extremely compact, silent, and low power (

WILEY2021

Thermal management of components for high energy physics experiments and space applications

Timothée Robert Sophus Frei

EPFL2021