Acoustically driven oscillatory flow fields in a cylindrical resonator at resonance.

Generation and development of acoustic waves in an air-filled cylindrical resonator driven by a conical electro-mechanical speaker are studied experimentally and simulated numerically. The driving frequencies of the speaker are chosen such that a standing wave field is produced at each chosen frequency in the resonator. The amplitude of the generated acoustic (pressure) waves is measured along the axis of the resonator by a fast response piezo-resistive pressure transducer, while the radial distribution of the oscillatory axial velocities is measured at the corresponding velocity anti-node locations by a constant temperature hot-film anemometer.

Experimental and numerical investigations of resonant acoustic waves in near-critical carbon dioxide.

Flow and transport induced by resonant acoustic waves in a near-critical fluid filled cylindrical enclosure is investigated both experimentally and numerically. Supercritical carbon dioxide (near the critical or the pseudo-critical states) in a confined resonator is subjected to acoustic field created by an electro-mechanical acoustic transducer and the induced pressure waves are measured by a fast response pressure field microphone. The frequency of the acoustic transducer is chosen such that the lowest acoustic mode propagates along the enclosure.

High amplitude nonlinear acoustic wave driven flow fields in cylindrical and conical resonators.

A high fidelity computational fluid dynamic model is used to simulate the flow, pressure, and density fields generated in a cylindrical and a conical resonator by a vibrating end wall/piston producing high-amplitude standing waves. The waves in the conical resonator are found to be shock-less and can generate peak acoustic overpressures that exceed the initial undisturbed pressure by two to three times. A cylindrical (consonant) acoustic resonator has limitations to the output response observed at one end when the opposite end is acoustically excited.

Development of artificial neural network based metamodels for inactivation of anthrax spores in ventilated spaces using computational fluid dynamics.

Linear, quadratic, and artificial neural network (ANN)-based metamodels were developed for predicting the extent of anthrax spore inactivation by chlorine dioxide in a ventilated three-dimensional space over time from computational fluid dynamics model (CFD) simulation data. Dimensionless groups were developed to define the design space of the problem scenario. The Hammersley sequence sampling (HSS) method was used to determine the sampling points for the numerical experiments within the design space.

Dielectrophoretic particle-particle interaction under AC electrohydrodynamic flow conditions.

We used the Maxwell stress tensor method to understand dielectrophoretic particle-particle interactions and applied the results to the interpretation of particle behaviors under alternating current (AC) electrohydrodynamic conditions such as AC electroosmosis (ACEO) and electrothermal flow (ETF). Distinct particle behaviors were observed under ACEO and ETF. Diverse particle-particle interactions observed in experiments such as particle clustering, particles keeping a certain distance from each other, chain and disc formation and their rotation, are explained based on the numerical simulation data.

Computational fluid dynamics analysis of the effects of reactor configuration on disinfection efficiency.

The efficacy of disinfection processes in water purification systems is governed by several key factors, including reactor hydraulics, disinfectant chemistry, and microbial inactivation kinetics. The objective of this work was to develop a computational fluid dynamics (CFD) model to predict velocity fields, mass transport, chlorine decay, and microbial inactivation in a continuous flow reactor. The CFD model was also used to evaluate disinfection efficiency in alternative reactor designs.

Analysis of Material Recovery in Plasma Arc Melting of Solid Wastes: A Computational Study.

Processing hazardous solid wastes in a DC arc melter offers several advantages over other competitive methods, including the ability to vary the mixture chemistry independently of the energy input. This decoupling allows the melter to be operated in conditions that enhance material recovery while continuing to provide robust waste destruction. This paper describes the use of a previously developed model to investigate the effect of chlorinated additives on metal volatilization in batch melters.

Modeling of Thermal Treatment of Hazardous Solid Wastes in a DC Arc Melter.

Ashley Wenger is a graduate student in the Mechanical Engineering and Mechanics (MEM) Department at Drexel University. Dr. Bakhtier Farouk is a professor in the MEM Department at Drexel University, 32nd and Chestnut Streets, Philadelphia, PA 19104.