Engineering Commons^™

An Investigation Of The Combined Heat And Mass Transfer Processes In The Drying Of Hygroscopic Porous Media With Two Disparate Length Scales, Thomas Joseph Phillips

Doctoral Dissertations

A mathematical model describing the drying process in a hygroscopic porous medium with two disparate length scales is formulated. The mathematical model is used to identify the important dimensionless parameters appearing in the problem; and, a parametric study is performed to determine the effects of varying these parameters on the drying process. Of particular interest in this study is to apply the model to the drying of large, round hay bales. Therefore a discussion of how the results of the parametric study impact on the efficient use of a hay drier is also presented.

The results from the parametric study …

The Influence Of Environmental Factors On The Temperature Of The Radiosonde Thermistor, James K. Luers

Doctoral Dissertations

A technique was developed to calculate the radiosonde temperature error as a function of altitude under different environmental conditions. The environmental conditions analyzed include the surface (or cloud) temperature, the atmospheric gaseous constinuents, the aerosol and thermodynamic structure of the atmosphere, the solar elevation angle, the solar albedo, the rise rate of the balloon, and the atmospheric density.

The heat balance equations for the thermistor and lead wires were derived and a sensitivity analysis performed to establish the significance of each heating term. The Air Force LOWTRAN 6 code was used to model the solar and infrared irradiation of the …

Air Stripping Of Volatile Organic Compounds From Groundwater: An Evaluation Of A Centrifugal Vapor-Liquid Contactor, Surinder Paul Singh

Doctoral Dissertations

The performance of a centrifugal vapor-liquid contactor equipped with high specific surface area packing (>2000 m²/m³) was evaluated for air stripping of jet fuel components from groundwater. Hydraulic test data indicated that the Sherwood flooding correlation which has been proposed for use in designing centrifugal vapor-liquid contactors overestimates the rotational speeds at which flooding occurs. For the mass transfer of performance, a concept of area of a transfer unit (ATU) was introduced to account for the change in fluid loading with radius of the packing torus. The ATU was found to be a strong function …

Heat Transfer Model And Computer Program For A Direct-Fired Rotary Kiln, Steven J. Kirslis

Masters Theses

An improved heat transfer model has been developed for a direct-fired rotary kiln. The model can be used to verify Kiln design, to optimize operating conditions, to predict the temperature history of the solids, and to evaluate if local areas of the kiln will be overheated. The treatment of radiant heat transfer was based on the Reflection Method developed by Succec and applied by Gorog, and was extended to account for radiation from a flame. Some elements of the Resistive Network Method and Zone Method were incorporated in the model. This method results in a more straightforward and flexible treatment …

A Proposed Solution To The Longitudinal Instabilities Of The Ball-Bartoe Jetwing Through The Addition Of A Thin, Fixed Slat To The Horizontal Tail, Steven L. Sisterman

Masters Theses

The Ball-Bartoe Jetwing research aircraft was developed as a STOL demonstrator vehicle employing single engine powered lift by means of upper surface blowing. Unfortunately, the aircraft has been plagued by longitudinal instabilities since the first flight. These instabilities have prevented an exploration of the full STOL potential of the aircraft since the problem becomes more severe during low airspeed flight.

A review of the historical data indicated that the instabilities may be attributed to the downwash flow that blanketed the horizontal tail in certain flight conditions. As the blown flaps were deflected to increase lift at low airspeeds, the resulting …

Characterization Of The Emission Properties Of Thermographic Phosphors For Use In High Temperature Sensing Applications, Alan Ronald Bugos

Masters Theses

Emission properties of fifteen different powder and crystalline thermographic phosphors have been characterized for potential use in high temperature sensing applications. Excitation and emission spectra of these rare-earth activated thermographic phosphors have been measured as a function of temperature using a special mini oven built inside of a fluorescence spectrophotometer. Several of the thermophosphors underwent decay lifetime analysis and were calibrated for use in high temperature measurements.

The excitation spectra taken from room temperature to approximately 400°C, reveal that the phosphors Y₂O₃:Eu³⁺, YV0₄:Eu³⁺, Ba₃(P0₄)₂:Eu …

Pilot Plant Demonstration Of A Combined Ca(Oh)2/Nh3 Based System For Desulfurization Of Flue Gas From High Sulfur Coal Applications, Arijit Pakrasi

Masters Theses

This study reports the preliminary results of a new approach to extend the usage of a Spray Dryer/Baghouse system to high sulfur coal applications. Pilot plant results are analysed and reported for a combined Ca(OH)₂/NH₃ injection system at inlet S0₂ concentrations of 2000 ppm and 3000 ppm in the flue gas. The results showed >90% overall S0₂ removal at average 91.6% sorbent utilization. Some concerns of a full scale system e.g. waste disposal, performance of the baghouse have been discussed. Areas of further study have been identified.