SEPARATION OF FINE LIQUID DROPLETS FROM HIGH SPEED AIR UTILIZING THE ELECTROHYDRODYNAMICS TECHNIQUE

With constant process intensification in recent years, the separation of fine micron and submicron size liquid droplets from gaseous flow mediums has become an important subject for the process and aerospace industries. While conventional technologies are not effective in this droplet size range, electrostatic separation demonstrated remarkable effectiveness and reliability while lowering maintenance and operation cost. However, it is commonly used for low droplet concentration in relatively low velocity gas flow. This current experimental study is focused on electrostatic separation of high concentration of fine electrically conductive droplets from high velocity gas flow. Different separators including wire-to-plate, wire-to-cylinder, single stage, and multi-stage separators were designed, built and tested at gas velocities up to 15 m/sec and droplet concentration up to 22,000 ppm. The results demonstrated that two-stage plate, as well as tubular separators provides maximum separation efficiency at minimum power consumption. However, the tubular separator is easier to package in the required space envelope and 1-inch diameter tubes are more efficient at high velocity and droplet concentrations

Effect of Milling on Electrostatic Separation and Modeling Protein and Starch Content of Flour Fractions

The objective of this research is to establish the effects of different milling techniques on the solvent-free electrostatic separation process for navy bean flour as well as to develop a model based on near infrared and fluorescence data to determine protein and starch content of the protein- and starch-enriched fractions using multivariate methods (i.e. partial least squares regression). Data fusion was used to combine the NIR and fluorescence spectra to try to achieve a model that had better predictability for protein and starch content. Protein content was measured using Kjeldahl digestion and starch content was measured using a dinitrosalicylic (DNS) acid array. The samples used in the NIR model are navy bean flour fractions from the electrostatic separation and the raw navy bean flour. There are 102 samples that are split in calibration (82 samples) and validation (20 samples) sets. The protein-enriched samples are collected from the electrostatic plate while the starch-enriched fractions are collected from the bottom of the electrostatic separator. The acquisition of reproducible infrared and fluorescence data from powder samples was successfully achieved. The pin milled navy bean flour had an average particle size almost three times smaller than the regular milled navy bean flour which could have contributed to the a high protein content (40.7%) of the protein-enriched fraction. The regular milled flour had a much higher protein extraction under optimum conditions but could only achieved a lesser protein content (32.5%) for the protein-enriched fraction. The regular milled navy bean flour also seemed to have particles disaggregate in the triboelectric charging process. Multivariate methods and pre-treatment techniques were compared for the NIR spectra of the navy bean flour fractions from electrostatic separation to measure the protein and starch content. The best method used Multiplicative Scatter Correction (MSC) pre-treatment with PLS regressions and had R2 values of prediction of 0.965 and 0.912 for protein and starch content, respectively. The N-way partial least squares (NPLS) regression was still a good model seeing as the R2 values of prediction for starch and protein content were 0.946 and 0.885, respectively. Two fluorophores were observed in navy bean flour: tryptophan and an unknown peak. It was observed that the starch model using the fluorescence dataset was highly correlated to the model’s predicted protein content (R2 of 0.978). The protein content model was better calibrated using the training set as well as providing a better prediction using the validation set for both NIR and fluorescence spectra. Data fusion was achieved by combining the NIR and unfolded fluorescence spectra of the navy bean flour fractions. The individual techniques had undergone pre-treatment separately and yielded the best model for determining protein content. Starch content was best determined using only the NIR spectra

CFD Modeling of Complex Chemical Processes: Multiscale and Multiphysics Challenges

Computational fluid dynamics (CFD), which uses numerical analysis to predict and model complex flow behaviors and transport processes, has become a mainstream tool in engineering process research and development. Complex chemical processes often involve coupling between dynamics at vastly different length and time scales, as well as coupling of different physical models. The multiscale and multiphysics nature of those problems calls for delicate modeling approaches. This book showcases recent contributions in this field, from the development of modeling methodology to its application in supporting the design, development, and optimization of engineering processes

電磁粒体の力学とその月・火星・小惑星に存在するレゴリスの操作技術に関する研究

早大学位記番号:新7464早稲田大

Research and Technology 1995

This report selectively summarizes the NASA Lewis Research Center's research and technology accomplishments for fiscal year 1995. It comprises over 150 short articles submitted by the staff members of the technical directorates. The report is organized into six major sections: aeronautics, aerospace technology, space flight systems, engineering support, Lewis Research Academy, and technology transfer. A table of contents, an author index, and a list of NASA Headquarters program offices have been included to assist the reader in finding articles of special interest. This report is not intended to be a comprehensive summary of all research and technology work done over the past fiscal year. Most of the work is reported in Lewis-published technical reports, journal articles, and presentations prepared by Lewis staff members and contractors (for abstracts of these Lewis-authored reports, visit the Lewis Technical Report Server (LETRS) on the World Wide Web-http://letrs.lerc.nasa.gov/LeTRS/). In addition, university grants have enabled faculty members and graduate students to engage in sponsored research that is reported at technical meetings or in journal articles. For each article in this report, a Lewis contact person has been identified, and where possible, reference documents are listed so that additional information can be easily obtained. The diversity of topics attests to the breadth of research and technology being pursued and to the skill mix of the staff that makes it possible. For more information about Lewis' research, visit us on the World Wide web-http://www.lerc.nasa.gov

Numerical simulation and physical analysis of the dispersion of charged inertial particles transported by stationary homogeneous isotropic turbulence

In this work, we study by numerical simulation the effect of electric charges on the dispersion of particles transported by a turbulent flow. The Navier-Stokes equations are solved by Direct Numerical Simulations (spectral approach) coupled with a Lagrangian solver in order to calculate the trajectories of each particle. A stochastic forcing scheme allows to obtain statistically homogeneous, isotropic and stationary turbulent flows. In the thesis, an original method to take into account electrostatic forces has been developed and validated on elementary configurations. In this method, the short-range interactions are estimated via a sum of the inter-particle interactions inside a cut-off distance and the long-range ones via a sum of interactions of particles with groups of particles which, at a distance greater than the cut-off distance, are considered as pseudo-particles. The convergence, the precision and the computational cost of the method have been studied in detail for its implementation for tri-periodic domains. The ensemble of these developments has been carried out in a parallel code which allows to perform simulations on a supercomputer of gas-particle flows containing up to $2\times 10^5$ particles. Firstly, the analysis of dry granular flows allowed to define a characteristic time scale of the effect of electric charges and to link it to the physical properties of the particles, in particular their diameter and agitation. The mechanism of transformation of the electric potential energy into particle kinetic energy is analyzed according to this time scale. Secondly, simulations of homogeneous isotropic turbulence transporting like-charged particles were carried out by varying their diameter (dynamic Stokes number) and their charge (electrostatic Stokes number). The simulations show that, for a given dynamic Stokes, the increase in particle charge leads to a decrease in their agitation since the electrostatic (repulsive) forces are conservative. The detailed analysis shows that, in fact, the electrostatic forces lead to a destruction of the fluid-particle velocity correlation which, according to the Tchen-Hinze theory, drives particle agitation. Besides agitation, the spatial distribution of particles is also considerably modified by electrostatic forces. In fact, the charges decrease the short-range values of the particle pair distribution function, which means that the phenomenon of preferential concentration of the particles is attenuated. In the limit of strong charges, it is even completely eliminated since electrostatic forces tend to uniformize the spatial distribution of the particles. This is because each particle tends to form an exclusion zone around it due to the strong repulsion at short distance. The relative velocity distribution functions of particle pairs are also affected by the presence of charges. Finally, the effect of the particle volume fraction is examined, where it is shown that its increase leads to a higher electric potential energy density stored the cloud of charged particles which leads to an increase of particle agitation

Bibliography of Lewis Research Center technical publications announced in 1985

This compilation of abstracts describes and indexes the technical reporting that resulted from the scientific and engineering work performed and managed by the Lewis Research Center in 1985. All the publications were announced in the 1985 issues of STAR (Scientific and Technical Aerospace Reports) and/or IAA (International Aerospace Abstracts). Included are research reports, journal articles, conference presentations, patents and patent applications, and theses

Proceedings of the 2018 Canadian Society for Mechanical Engineering (CSME) International Congress

Published proceedings of the 2018 Canadian Society for Mechanical Engineering (CSME) International Congress, hosted by York University, 27-30 May 2018

NASA Tech Briefs, April 2002

The contents include: 1) Application Briefs; 2) Sneak Preview of Sensors Expo; 3) The Complexity of the Diagnosis Problem; 4) Design Concepts for the ISS TransHab Module; 5) Characteristics of Supercritical Transitional Mixing Layers; 6) Electrometer for Triboelectric Evaluation of Materials; 7) Infrared CO2 Sensor With Built-In Calibration Chambers; 8) Solid-State Potentiometric CO Sensor; 9) Planetary Rover Absolute Heading Detection Using a Sun Sensor; 10) Concept for Utilizing Full Areas of STJ Photodetector Arrays; 11) Development of Cognitive Sensors; 12) Enabling Higher-Voltage Operation of SOl CMOS Transistors; 13) Estimating Antenna-Pointing Errors From Beam Squints; 14) Advanced-Fatigue-Crack-Growth and Fracture- Mechanics Program; 15) Software for Sequencing Spacecraft Actions; 16) Program Distributes and Tracks Organizational Memoranda; 16) Flat Membrane Device for Dehumidification of Air; 17) Inverted Hindle Mount Reduces Sag of a Large, Precise Mirror; 18) Heart-Pump-Outlet/Cannula Coupling; 19) Externally Triggered Microcapsules Release Drugs In Situ; 20) Combinatorial Drug Design Augmented by Information Theory; 21) Multiple-Path-Length Optical Absorbance Cell; 22) Model of a Fluidized Bed Containing a Mixture of Particles; 23) Refractive Secondary Concentrators for Solar Thermal Systems; 24) Cold Flow Calorimeter; 25) Methodology for Tracking Hazards and Predicting Failures; 26) Estimating Heterodyne-Interferometer Polarization Leakage; 27) An Efficient Algorithm for Propagation of Temporal- Constraint Networks; 28) Software for Continuous Replanning During Execution; 29) Surface-Launched Explorers for Reconnaissance/Scouting; 30) Firmware for a Small Motion-Control Processor; 31) Gear Bearings and Gear-Bearing Transmissions; and 32) Linear Dynamometer With Variable Stroke and Frequency