Cecilia D. Richards - US grants

Cecilia Richards Abstract The objective of this research is to investigate the effect of vortex dynamics on droplets dispersion, vaporization, and burning in round jets. The research will focus on the dispersion of drop and their vapor by large-scale vortical structures in nonreacting jet, and in reacting jets, and on the impact of droplet/eddy interaction on the reacting flow structure. An experimental study of a turbulent jet with point source droplet stream injection using planar imaging techniques, image analysis, and point measurements of droplet and gas phase statistics, will be performed. This research will yield insight on the effect of vortex dynamics on the structure and behavior of reacting two-phase flows, data from this study will be directly applicable to improved design of two-phase reacting devices, such as industrial furnaces, gas turbine combustors, and hazardous waste incinerators.

9412070 Richards This equipment will be used in studies of turbulent mixing phenomena (single and two phase) in nonreacting and reacting shear flows. Two major projects will extensively employ this equipment. These are: (1) droplet dispersions by large scale structures in reacting and nonreacting jets; and (2) dynamics of a scalar field in a swirling jet. Besides these two projects, it is anticipated that the equipment will provide broad support to faculty doing experimental fluid mechanics research. ***

ABSTRACT CTS-9457108 Cecilia Richards Turbulent dispersion of droplets in turbulent jets, and particle behavior in two-phase reacting flows, will be experimentally investigated. Dr. Richards will implement various design components in her teaching of undergraduate and students. ***

The goal of this Engineering Microsystems: "XYZ" on a Chip project is to investigate the fabrication of a micro heat engine, which will use commonly available liquid hydrocarbon fuels, to efficiently generate electric power to be used by Micro-Electro-Mechanical Systems (MEMS) and microelectronic devices. This micro heat engine is expected to deliver electric power in the range of milliwatts to watts while supplying voltages from 1 to 30 volts. The research involves the creation of a totally new class of heat engine, which takes advantage of thermophysical phenomena unique to small scales.

The result will be a heat engine that is efficient and that can be mass-produced with techniques developed for microelectronics and MEMS. The proposed engine is an external combustion engine, in which thermal power is converted to mechanical power through the use of a novel thermodynamic cycle which approaches the ideal vapor Carnot cycle. Mechanical power is converted into electrical power through the use of a piezoelectric generator. The generator, which takes the form of a flexible membrane, can be readily manufactured using MEMS fabrication techniques but still delivers high conversion efficiency. This approach eliminates the requirement to manufacture complex micromachines such as rotary compressors and turbines, resulting in a very simple but highly efficient device. In addition, since the micro heat engine is an external combustion device, it will have broad fuel flexibility, making it useful in a wide range of applications including military, space, biomedical, and consumer products.

Abstract
CTS-9978814
C.T. Crowe, C.D. Richards and T.R. Troutt

The objective of the proposed project is to improve turbulence modeling by using gravitational settling of particles as a simple flow experiment and adopting several new concepts in the simulation of turbulence dissipation. Particles with the same index of refraction as the fluid are to be released into a quiescent fluid at a steady rate over the entire cross-section of the tank. A three-dimensional Particle Image Velocimetry (PIV) will be used to measure fluid velocity in the tank. A small fraction of solid particles will be marked with a reflective coating for tracking. The measurement will provide the volume averaged components of the turbulence energy and the components of the Reynolds stress for liquid and particles in a zone where the turbulence is established. The effect of interparticle distance on turbulence dissipation will be evaluated. A12-month award will provide the proof of concept of the three-dimensional two-phase PIV measurements.

Abstract

Proposal Number: CTS-0404370
Principal Investigator: Cecilia D. Richards
Affiliation: Washington State University
Proposal Title: NIRT: Nanotube based structures for high resolution control of thermal transport

This proposal was received in response to Nanoscale Science and Engineering initiative, NSF 03-043, category NIRT. The focus of this work is the use of mixed-scale architectures to bridge scales from nanometer level structures to micrometer level components to millimeter level devices and materials. We propose to incorporate carbon nanotubes into microscale composites to create a new kind of mesoscale device, a thermal switch. Arrays of thermal switches will then be produced in batch to create sheets with spatially and temporally controllable "digital" thermal conductivity.
Mixed-scale architectures can be used to bridge scales from nanometers to micrometers to milimeters in order to manufacture materials and devices whose pertinent dimensions range from nanoscale to microscale to mesoscale. Carbon nanotubes (CNT's) are inherently one-dimensional mixed-scale structures, with diameters in the range of nm and lengths in the range of mm. We take advantage of this 103 aspect ratio to bring superior thermal and mechanical properties (due to the CNT's nanometer scale diameters), to micro-scale components (making use of the CNT's micrometer scale lengths). Many microelectromechanical systems (MEMS) are also inherently two-dimensional mixed-scale structures with thicknesses in the range of mm and planar dimensions in the range of mm. We take advantage of this 103 aspect ratio, to bring the superior thermal and mechanical properties of the micro-scale components to effective use on the meso-scale.
Carbon nanotubes will be synthesized and then extensively characterized. The nanoscale thermal and mechanical properties of the CNT's will be modeled. The CNT's will then be assembled into aligned arrays within a matrix and formed into micron scale blocks. The thermal and mechanical properties of the aligned CNT composite blocks will then be characterized and modeled. Finally, the CNT composite blocks will be utilized to fabricate prototypes of thermal switch devices.
The educational plan targets undergraduates, under represented groups, K-12, and teachers. This work will result in strong interactions between a large, rural research institution and two urban campuses, making it easier for students from a wide range of demographics to participate in cutting edge research projects. Instrumentation for characterizing thermo-mechanical responses of nanotube assemblies will be created, allowing future work to proceed in these areas. High school teachers from the Northwest will be able to get hands on tools to bring nanotechnology back to their schools, helping to motivate future generations of scientists and engineers. Research on this project will closely couple undergraduates and graduate students, helping to foster integrating research into all levels of education, particularly in groups traditionally under-represented from science and engineering.

The research is being funded by the Thermal Transport and Thermal Processing Program of the Chemical and Transport Systems Division.

EEC-0754370
Cecilia D. Richards

This three year REU Site program will expose ten undergraduate students each year to basic concepts in the emerging field of multiscale science and engineering and will provide them with intensive hands-on research experience. The students will have an opportunity to work in a multidisciplinary environment with a range of mentors (faculty, post docs and graduate students) on projects ranging from material processing, fabrication and testing, microfluidic and MEMS devices, nanoindentation and atomic force measurements, to introduction to design algorithms for nano-macro-structured materials, molecular dynamics, dislocation dynamics, mesoscale analyses for deformation and flow in nano and macro structures.

Students will participate in a weekly forum where they will give short overviews/updates of their projects and develop their oral technical communication skills. They will also participate in a joint activity with the NSF sponsored Engineering Education Research Center (EERC) to gain exposure to another emerging area of engineering research. The participants will disseminate the results of their independent research projects in a campus wide poster session.

This three year REU Site award at Washington State University (WSU) entitled "Introduction to Multiscale Engineering, is dedicated to using modern processing, modeling and analysis techniques to understand the relationships between the structure and properties at various length scales spanning the spectrum from the atomic scale to the macroscopic scale. Ten undergraduate students will participate each summer in individual projects over the course of 10 weeks. A group of 9 faculty members in the College of Engineering and Architecture at WSU will be dedicated to mentoring and research supervision. Each project will introduce the student to basic concepts in multiscale engineering and, thus, each project will include components (experimental and/or analytical and numerical) that deal with at least two different length scales. Students will work with a team including faculty, post docs and graduate students on projects such as multiscale models of materials behavior, discrete particle simulation of granular materials, collective behavior of carbon nanotubes, mechanical behavior of sheet metals under dynamic loading, modeling and simulation of microfluidic fuel cells, thermoacoustic electricity generators, scaling of hydrogenic twin-screw extruders for the fueling of fusion energy machines, fabrication and characterization of thermal interface materials, scaling issues in resonant heat engines, and multiscale effects in composite laminates.

This REU Site program will provide a research experience for a diverse group of students, ranging from ethnicity, gender, academic, and economic backgrounds. Recruitment efforts will focus on students from demographic groups traditionally underrepresented in engineering and science, students from schools that have limited research, and students who are 1st and 2nd year undergraduates who are often not given research opportunities. The goal for this REU site is to increase participation by underrepresented groups from the current 45% to over 50%. In particular, the program will increase participation by Hispanic students through mentoring programs. By actively recruiting students who have finished their first and second years, the program aims to attract students to engineering who otherwise might have changed majors later in their undergraduate studies. This strategy is designed to attract and retain students from many disciplines of engineering and science to careers in multiscale science and engineering.