FLOW DISTRIBUTION CONTROL IN MESO SCALE VIA ELECTROHYDRODYNAMIC CONDUCTION PUMPING

Electrohydrodynamic (EHD) conduction pumping offers a unique way to control flow distribution for heat transfer applications. In EHD conduction, the interaction between an applied electrical field and dissociated electrolyte species in a dielectric fluid creates a net body force within the fluid, resulting in flow. EHD conduction pumps have remarkable potential due to their lack of moving parts, low power use, and ability to operate in microgravity. This study examined EHD distribution control among three 1 mm-diameter parallel tubes. The EHD pumps were able to correct maldistributed flow in flow lines and were able to cause maldistribution in lines where even flow was initialized. The EHD pumps were operated between 0V and 1500V with flow rate supplies of 3mL/min and 25mL/min

Flow Distribution Control in Meso Scale via Electrohydrodynamic Conduction Pumping

Electrohydrodynamic (EHD) conduction pumping offers a unique way to control flow distribution for heat transfer applications. In EHD conduction, the interaction between an applied electrical field and dissociated electrolyte species in a dielectric fluid creates a net body force within the fluid, resulting in flow. EHD conduction pumps have remarkable potential due to their lack of moving parts, low power use, and ability to operate in microgravity. This study examined EHD distribution control among three 1 mm-diameter parallel tubes. The EHD pumps were able to correct maldistributed flow in flow lines as well as being able to cause maldistribution in lines where even flow was initialized. The supply flow rates between 3mL/min and 25mL/min

FLOW DISTRIBUTION CONTROL IN MESO SCALE VIA ELECTROHYDRODYNAMIC CONDUCTION PUMPING

Electrohydrodynamic (EHD) conduction pumping offers a unique way to control flow distribution for heat transfer applications. In EHD conduction, the interaction between an applied electrical field and dissociated electrolyte species in a dielectric fluid creates a net body force within the fluid, resulting in flow. EHD conduction pumps have remarkable potential due to their lack of moving parts, low power use, and ability to operate in microgravity. This study examined EHD distribution control among three 1 mm-diameter parallel tubes. The EHD pumps were able to correct maldistributed flow in flow lines and were able to cause maldistribution when even flow was initialized. The EHD pumps were operated between 0V and 1500V with flow rate supplies of 3mL/min and 25mL/min

Terrestrial and Micro-Gravity Studies in Electrohydrodynamic Conduction-Driven Heat Transport Systems

Electrohydrodynamic (EHD) phenomena involve the interaction between electrical and flow fields in a dielectric fluid medium. In EHD conduction, the electric field causes an imbalance in the dissociation-recombination reaction of neutral electrolytic species, generating free space charges which are redistributed to the vicinity of the electrodes. Proper asymmetric design of the electrodes generates net axial flow motion, pumping the fluid. EHD conduction pumps can be used as the sole driving mechanism for small-scale heat transport systems because they have a simple electrode design, which allows them to be fabricated in exceedingly compact form (down to micro-scale). EHD conduction is also an effective technique to pump a thin liquid film. However, before specific applications in terrestrial and micro-gravity thermal management can be developed, a better understanding of the interaction between electrical and flow fields with and without phase-change and in the presence and absence of gravity is needed. With the above motivation in mind, detailed experimental work in EHD conduction-driven single- and two-phase flow is carried out. Two major experiments are conducted both terrestrially and on board a variable gravity parabolic flight. Fundamental behavior and performance evaluation of these electrically driven heat transport systems in the respective environments are studied. The first major experiment involves a meso-scale, single-phase liquid EHD conduction pump which is used to drive a heat transport system in the presence and absence of gravity. The terrestrial results include fundamental observations of the interaction between two-phase flow pressure drop and EHD pump net pressure generation in meso-scale and short-term/long-term, single- and two-phase flow performance evaluation. The parabolic flight results show operation of a meso-scale EHD conduction-driven heat transport system for the first time in microgravity. The second major experiment involves liquid film flow boiling driven by EHD conduction in the presence and absence of gravity. The terrestrial experiments investigate electro-wetting of the boiling surface by EHD conduction pumping of liquid film, resulting in enhanced heat transfer. Further research to analyze the effects on the entire liquid film flow boiling regime is conducted through experiments involving nanofiber-enhanced heater surfaces and dielectrophoretic force. In the absence of gravity, the EHD-driven liquid film flow boiling process is studied for the first time and valuable new insights are gained. It is shown that the process can be sustained in micro-gravity by EHD conduction and this lays the foundation for future experimental research in electrically driven liquid film flow boiling. The understanding gained from these experiments also provides the framework for unique and novel heat transport systems for a wide range of applications in different scales in terrestrial and microgravity conditions

Next Generation, Smart Fluid Storage Tank for Space and Terrestrial Applications

Technology which utilizes the electrohydrodynamic (EHD) phenomena is smart and self-driven. In 2020, NASA will be sending this satellite and space technology to the ISS for testing. Our project explores the application of EHD conduction pumping to mix fluids non-mechanically in the absence of gravity.Our EHD embedded spherical tank design actively homogenizes the temperature within and avoids vaporization of the liquid. The EHD conduction pumping mechanism provides fluid circulation via the dissociation of electrolytes when subjected to an electric field. Through temperature and velocity measurements from 0 to 9,000 V, EHD mixing can be quantified for our Major Qualifying Project. The testing proves that this technology is viable and paves the way for future advancements in the field

Micro- and Nano-Scale Electrically Driven Two-Phase Thermal Management

This presentation discusses ground based proof of concept hardware under development at NASA GSFC to address high heat flux thermal management in silicon substrates. The goal is to develop proof of concept hardware for space flight validation. The space flight hardware will provide gravity insensitive thermal management for electronics applications such as transmit receive modules that are severely limited by thermal concerns

ELECTROHYDRODYNAMIC PUMPING PRESSURE GENERATION

Electrohydrodynamic (EHD) conduction pumping relies on the interaction between electric fields and dissociated charges in dielectric fluids. EHD pumps are small, have no moving parts and offer superior performance for heat transport. These pumps are therefore able to generate high mass flow rates but high pressure generation is difficult to achieve from these devices. In this Major Qualifying Project, a macro-scale, EHD conduction pump capable of generating up to 400 Pa per section was designed, built and tested. The pump is comprised of pairs of porous, 1.6mm wide high-voltage electrodes with a pore size of 10µm and 3.7mm long flush, ring ground electrodes, spaced 1.6mm apart. The space between pairs is 8mm, with 8 pairs per section. The working fluid is the Novec 7600 engineering fluid

Fluid Flow Distribution Control in Micro-Scale with EHD Conduction Pumping Mechanism

Electrohydrodynamic (EHD) conduction pumping technology utilizes the interaction between an applied electrical field and dissociated ions within a dielectric fluid to generate a net body force within the fluid, which results in a net flow. EHD conduction pumps have noticeable benefits when compared to their traditional mechanical counterparts due to their low vibration and noise generation, low power consumption, and ability to operate in microgravity. EHD conduction pumps provide intelligent flow control via their ability to vary the electric field voltage applied to their electrodes. The purpose of this Major Qualifying Project was to study the use of EHD conduction pumps in controlling single phase flow distribution through parallel micro-channels using upstream micro-scale EHD pumps

Development of Advanced Spacecraft Thermal Subsystems

This presentation discusses ground based proof of concept hardware under development at NASA GSFC to address high heat flux thermal management in silicon substrates and embedded thermal management systems. The goal is to develop proof of concept hardware for space flight validation. The space flight hardware will provide gravity insensitive thermal management for electronics applications such as transmit/receive modules that are severely limited by thermal concerns