Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase I | Award Amount: 80.00K | Year: 2016
When a payload exits a submerged launch tube, pressurized gas follows the ejected projectile into the surrounding water and expands between the tube and the upward moving projectile. The gas cavity behind the moving body then deforms and pinches off from the tube and then collapses with the formation of a strong upward reentrant jet. The impact of the high-speed reentrant jet on the projectile presents a threat of damage and imparts an unwanted force to its motion. Previously attempted high speed photography of the reentrant jet has not been successful due to the highly opaque and turbulent bubbly region surrounding the cavity. In order to alleviate this deficiency, we propose in this SBIR to combine high speed video observations of the cavity dynamics with pressure measurements in the water at several locations and impact pressure measurements on the projectile base. The optical method will provide the exterior shape of the evolving cavity, while the acoustic method, combined with a CFD computation of the cavity shape evolution for different input conditions, will enable reconstruction of the reentrant jet shape evolution in space and time using inverse problem optimization techniques that process both the acquired video and the acoustic information. The system will be tested and validated in Phase I using an available small scale uncorking setup in a vacuum tank and then scaled up for the field tests.
Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase II | Award Amount: 70.00K | Year: 2016
Under a recently completed ONR SBIR Phase II a non-abrasive diver tool for propeller cleaning was developed using DYNAFLOWs cavitating and resonating waterjets. This non-abrasive tool uses the collapse of cavitating microstructures in the submerged jet over the fouling to remove it. It also uses a self-rotating head to achieve high removal rates, a counter-thruster to reduce diver fatigue, and a silencer to reduce noise. The tool was extensively tested on surrogate fouling on NAB plates and on a fouled propeller in the laboratory. Finally field tests were conducted on the USS Leyte Gulf. Recommendation from those tests were to reduce weight and length of the tool for ergonomic considerations. Further R&D since has addressed these recommendations and significantly improved removal ratesIn the proposed effort, the improved tool will be first tested at DYNAFLOW on an APU propeller, then, in coordination with NAVSEA cleaning tests will be conducted on a Navy ship in Norfolk. A well performing pump will be rented and Navy cleared divers from Seaward Marine will conduct tests with the tool and record videos of its performance on the Navy propeller. A report of this effort will be delivered following completion of the tests.
Agency: Department of Energy | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 150.00K | Year: 2015
Development of algae as a source of renewable chemicals and fuels is hindered by the difficulty of recovering the algae from the growth solutions. Air flotation can separate solids and liquids by having gas bubbles attach to the solid particles to increase buoyancy and lift them to the surface. The small particle sizes of algae require that small bubble sizes be used. Conventionally very fine bubbles are created using dissolved gas flotation DAF). DAF requires high pressures to supersaturate gases into water and has poor energy efficiency. However, this can be overcome by using bubble generators based on local controlled hydrodynamic cavitation to generate large volumes of very small bubbles with much less energy. These will have long residence time in the water, rise slowly in the gravity field while attaching to the algae cells and lifting them to the free surface. In this proposed Phase I SBIR project, we will investigate the feasibility of using a bubble generator concept based on controlled cavitation to remove water and concentrate the algae from the growth media and recover the intact cells. The objectives of the project will be to design and construct a bench- scale algal growth media dewatering loop with the bubble generator capable of producing large numbers of bubble of diameters less than 50 microns, and to then move to pilot scale systems after addressing R&D issues. A controlled cavitation bubble generator will be tested. The bubble sizes and numbers produced will be diagnosed by high speed video, image analysis, and acoustic techniques. The effects of operating parameters pressure drop, air and water flow rates) on bubble size distributions will be determined. The performance of the solid- liquid separation system with different algae species, algae concentrations, and air-liquid void fractions will be determined. The percent recovery of algae form solution, percentage of solids in the recovered slurry, and algae quality will be measured in these experiments. If necessary to increase the percentage of solids to 20% secondary concentration methods such as vacuum filtration will be tested. An energy efficient method for dewatering algae solutions will reduce the production costs for renewable chemicals and fuels produced from algae, and reduce the barriers to bringing this technology to commercial scale. The separation technology developed in this SBIR would also have applications in other fields such as mining, wastewater treatment, and petroleum process water treatment.
Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase I | Award Amount: 149.98K | Year: 2012
We propose to develop a propeller cleaning system using DYNAFLOW"s advanced cavitating and resonating waterjet technology. This non-abrasive technology generates cavitating microstructures in the jet flow at low jet pressures, thus avoiding problems with high jet impact pressures. It utilizes acoustic resonance, jet structuring, and swirl flow generation to enhance the cavitation intensity. The resulting bubble and vortex clouds collapse over the fouling and remove it. The DYNAJETS are effective at both very high and very low pump pressures depending on the fouling to remove. We propose to arrange the nozzles on rotating disks in an arrangement that allows self-induced disk rotation to increase coverage, simplify diver efforts, and clean the propeller surface efficiently and safely. A key strength of our approach is our fundamental and applied long term involvement with cavitation, erosion, and cavitating jet studies, which will enable us to develop an adaptable DYNAJETS tool where the jet operation conditions can be tuned to the types of fouling to optimize cleaning operation efficiency while protecting the underlying propeller material surface. In Phase I, the feasibility of such a DYNAJETS diver tool will be demonstrated, and the concept design will be developed through systematic experiments on fouled NAB plates.
Agency: Department of Energy | Branch: | Program: SBIR | Phase: Phase II | Award Amount: 1000.00K | Year: 2012
Multiphase bubbly mixture flows are of importance in turbomachinery, pipelines, cooling systems, reaction towers, as well as in various applications in petroleum, chemical, geothermal, and nuclear industries. The presence of the gaseous component has a strong influence on performance and efficiency. The ability to predict the flow behavior accurately is essential in designing energy efficient two-phase flow process equipment. A major difficulty in modeling and simulation of such flows lies in the complex multiple lengths and multiple time scale nature of such flows. Conventional scientific and engineering approaches concentrate on either macroscopic averaged quantities or focus on two- phase interface tracking of identified important flow details and do not address the full flow. Therefore, a comprehensive model, which could resolve simultaneously the important scales, is required. The proposed research will develop a multi-scale two-phase flow simulation method capable of accurately representing bubbly flows at the various scales. The model will include a continuum- based phase averaged model for the macro-scales and a discrete bubble/particle model for the micro-scales. These will be integrated into a single code that automatically switches between the two models at different times or in different locations of the studied geometry and allows conversion of discrete bubbles into a continuum description or a liquid-gas free surface, and vice versa, depending on bubble and cavities evolution and space concentration. Commercial Applications and Other Benefits: A multi-scale approach based on state-of-the-art numerical techniques will result in a commercial code for generalized bubble flow simulations which can accurately capture important characteristics of cavitating and high void fraction multiphase flows. This software will be able to describe dilute mixtures as well as mixtures that result in large cavities, bubble clouds, separated flows, etc. This software will enable researchers in chemical, oil and gas, nuclear, and marine industries to conduct design studies and to improve energy efficiency of their processes and devices. These applications will strengthen the competitiveness of US industries equipped with advanced systems.
Agency: Department of Energy | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 150.00K | Year: 2012
Intense pulsed pressure waves induced by proton beam impact on mercury in a spallation target propagate in the mercury and reflect from vessel walls as expansion waves resulting in cavitation damage to the walls. Injection of gas bubbles (few micrometer diameter range and void fraction of the order of 1%) into the mercury flow is one of the promising methods under investigation to mitigate the damage. Due to the opacity of mercury, a non-optical diagnostic tool is needed to quantify the injected bubble populations. The fact that bubbles have strong effects on acoustic wave propagation makes acoustic methods very good candidates for this application. This project will develop an acoustic diagnostic tool that can meet all the bubble sizing requirements for Spallation Neutron Source (SNS) applications. It will build on the technology of the present state-of-the-art acoustic bubble sizing instrument, the ABS ACOUSTIC BUBBLE SPECTROMETER, which works well for void fractions of the order of 0.1% and for bubbles between 20 and 500 m in diameter. The new instrument will use a nonlinear bubble dynamics model that extends the current linear theory utilized in the present ABS system to fully account for large bubble oscillations, bubble interactions, and strong acoustic damping. It will also use artificial intelligence (neural networks) to help solve the acoustic inverse problem and improve measurement accuracy and speed. Additionally, the proposed new method will investigate a wave reflection scheme which has the potential to outperform the wave transmission scheme currently used in ABS systems in high void fraction conditions. An acoustic instrument that is capable of measuring a wide range of bubble sizes at high void fraction will be a valuable tool for diagnostic and control of numerous multi-phase flow and liquid metal applications. Successful development of the proposed instrument will have wide commercial and scientific applications and benefits. In addition to the SNS application, the instrument will find application in oceanographic, biological, chemical, pharmaceutical, and other industrial fields.
Agency: Department of Energy | Branch: | Program: SBIR | Phase: Phase II | Award Amount: 1.00M | Year: 2013
In the Spallation Neutron Source, the mercury in the stainless steel target vessel experiences cavitation due to intense pressure waves produced by the almost instantaneous heating of the mercury following proton impact on the target. To protect the vessel walls from cavitation erosion, helium micro bubbles can be added to the mercury to act as attenuators of the pressure waves and to minimize cavitation effects. A diagnostic method is needed to monitor the gas injection technique and to measure the bubble size distribution. This project will develop an acoustic diagnostic tool that can meet the bubble size and void fraction requirements of the Spallation Neutron Source application. To enable use of larger amplitude acoustics waves and overcome excessive damping in the bubbly mixture, a non-linear acoustic theory and an intelligent artificial neural network using a priori knowledge from the acoustic theory will be used to extract bubble size distribution from acoustic data. Both acoustic wave transmission and reflection methods will be investigated and used to enable measurement at a range of void fractions that are often encountered in two-phase flow applications. During the Phase I study, significant progress was made in extending the capabilities of the acoustic bubble spectrometer hardware for a wider range of bubble sizes and void fractions, and in adapting it for the DOE mercury application. A non-linear bubble dynamics model that extends the linear theory utilized in the present spectrometer was developed and demonstrated. The feasibility of using a neural network based inverse problem solver to measure bubble size distribution was demonstrated using both synthetic and experimental data. The feasibility of using reflection waves to measure bubble size distribution and void fraction was also demonstrated; and theoretical formulations to interpret reflected sound wave signals to use in the inverse problem solver development were initiated. In Phase II the hardware of the spectrometer will be further improved to upgrade high frequency signal generation (for smaller bubble size measurements) and lower frequency hydrophones (for large bubble size measurement); and better designed integrated hydrophone for reflection tests. This will enable development of high fidelity databases for training and validating the neural network based spectrometer. The 3-D nonlinear acoustic model will be expanded to simulate practical geometries encountered in spectrometer operation and provide databases for training and testing the neural network in regimes where linear acoustic theory does not apply. Finally, the acoustic reflection method initialized in Phase I will be further developed, tested, and implemented in the new generation acoustic bubble spectrometer being developed. Commercial Applications and Other Benefits: A marketable acoustic instrument capable of measuring a wide range of bubble sizes and void fractions will be a valuable tool for diagnostics and control of numerous multi-phase flow and liquid metal applications. Successful development of the proposed instrument will have wide commercial and scientific applications and benefits. In addition to the Spallation Neutron Source application, the instrument will find applications in oceanographic, biological, chemical, pharmaceutical, energy, and other industries.
Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase II | Award Amount: 500.01K | Year: 2013
The propeller cleaning system developed in this project uses DYNAFLOW"s advanced cavitating and resonating waterjet technology. This non-abrasive technology uses the growth and collapse of cavitating microstructures in the submerged jet over the fouling to remove it. In Phase I, we successfully demonstrated the feasibility of such a DYNAJETS diver tool with self-rotating multi-nozzle heads and developed the concept design through experiments on surrogate fouled NAB plates. The design allows self-induced rotation to increase coverage, simplify diver efforts, and clean the propeller surface efficiently and safely. In the proposed Phase II development work, we will conduct more systematic tests to improve the efficiency and ergonomic of this tool concept further and develop a prototype system, which will be built and tested in field during Phase II Option. Our fundamental and long term involvement with cavitation, erosion, and cavitating jet studies will enable us to develop an adaptable DYNAJETS diver tool which allows tuning of the tool and the operation conditions depending on the types of fouling to optimize cleaning effectiveness while protecting the underlying NAB surface.
Agency: NSF | Branch: Standard Grant | Program: | Phase: | Award Amount: 180.00K | Year: 2011
This Small Business Innovation Research Phase I project will develop a method for lysing algae and recovering the oil without pre-concentrating or dewatering. A promising feedstock for biofuels is photosynthetic algae, which can produce lipids in much higher yields per acre then can terrestrial crops. Currently, the harvesting and extracting of the oil consumes 40%-60% of the energy required to produce biodiesel from algae. If the lipids and other compounds can be collected directly from the growth media these expenses would be entirely avoided. Cavitation is a good candidate as it has been shown to rupture algal cell membranes and release cell contents. Feasibility of hydrodynamic jet cavitation as a practical and easily scalable method will be demonstrated. This process will be inline and will use shear flow and local accelerations to create high pressure fluctuations in the liquid causing bubbles to grow and collapse using a fraction of the energy required for ultrasonic cavitation. Hydrodynamic submerged jet cavitation also creates clouds of fine microbubbles that can attach to lipids and lift them to the surface. By controlling the creation and collection of foam, the lipids can be concentrated and recovered from the growth media with minimal energy input.
The broader impact/commercial potential of this project is the development of new fuel resources that would benefit the nation by providing a stable energy source, reducing gas imports and dependence on foreign nations, and reducing greenhouse gas emissions. Commercialization of microalgae for biofuels and nutritional uses is expanding rapidly in the USA and the world. Eliminating the major energy requirements of harvesting and extraction will increase the profitability of biofuel production from algae. Providing a technology capable of achieving this will be very marketable. This technology could also be applied to other biotechnologies in which microorganisms are used to produce high value products, such as pharmaceuticals, nutraceuticals, or biorefining. This process could be used for more economical and more sustainable use of bioresources. In addition, greater understanding of the behavior of microorganisms in hydrodynamic flows would benefit the fields of biotechnology, health care, and water purification.
Agency: Department of Energy | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 150.00K | Year: 2016
Wet organic wastesuch as biosolids from wastewater treatment plants, manure slurries, and food and beverage production have the potential to be a useful feedstock for the production of biofuels and other bioproducts. Hydrothermal liquefaction using subcritical water can be used to extract the bioproducts from the wet waste without the need for expensive drying processes. However, it is difficult to scale subcritical water extraction processes due to poor mass transfer between the solvent and the biomass particles, degradation of the bioproducts at the high temperatures and pressures required to decrease the permittivity of water, and need for expensive materials, such as Inconel, to construct reactors able to withstand these high temperatures and pressures. One potential method of increasing the extraction efficiency of subcritical water extraction of wet organic waste is the application of hydrodynamic cavitation to the subcritical fluid in order to generate transient local regions of high temperature and pressure where the biomass would be dissolved at relatively low bulk ambient temperatures. HOW THIS PROBLEM IS BEING ADDRESSED: In this proposed Phase I SBIR project, we will investigate the feasibility of using cavitation in the subcritical fluid to break apart solid particles, produce transient high temperatures and pressures that will reduce the permittivity of water and increase mass transfer rates with better mixing. First, cavitation will be applied to reduce the particle sizes of the biosolids and increase the surface area of the particles and the rate of xtraction. Second, the collapse of the bubbles generated during cavitation will create transient regions of high temperature and pressure where the solvent properties of the sub-critical water will be non-polar without the need for higher temperatures in the entire reactor which can degrade the final products. Mass transfer rates will be increased in the fluid due to turbulent mixing. Additionally, if better extraction can be achieved at lower temperatures and pressures in the bulk fluid then cheaper materials of construction could be used to build the reactors. The concept will them be moved to pilot scale systems after addressing R&D issues. WHAT IS TO BE DONE IN PHASE I: The objectives of the project will be to design and construct a subcritical water reactor with specially designed cavitating jets capable of generating cavitation in pressurized water at relatively low pressures and demonstrate the extraction of wet organic waste. Cavitation will be generated in specially designed highly efficient nozzles. During cavitation, bubbles will form in the fluid, expand explosively, then collapse abruptly creating regions of high temperature and pressure within the fluid near the surface of the biomass particles. These nozzles will allow the generation of cavitation in the bulk fluid using relatively low pumping pressures. Thus, using cavitation to enhance subcritical water extraction will be more economical than increasing the temperature and pressure of the entire reactor. The reactor and process design will be helped with numerical simulations of the reactor flow field and of bubble / particle interactions in the wet organic waste. COMMERCIAL APPLICATION AND OTHER BENEFITS: Improving the energy efficiency of subcritical water extraction of biomass with high water content will reduce the production costs for renewable chemicals and fuels produced from wet organic waste. This will reduce the barriers to bringing this technology to commercial scale. The extraction technology developed in this SBIR would also have applications in other fields such as natural product recovery, analytical chemistry equipment, and algae biofuels production. KEYWORDS: subcritical water, biomass, biofuels, organic waste, cavitation