Charles Cook | Louisiana State University (original) (raw)

Papers by Charles Cook

Research paper thumbnail of In Situ Velocity Measurements from an Industrial Rotary Kiln Incinerator

Journal of the Air & Waste Management Association, 1995

For the first time, velocities were measured inside a fieldscale rotary kiln incinerator. Combust... more For the first time, velocities were measured inside a fieldscale rotary kiln incinerator. Combustion gas velocities and temperatures were measured at multiple points across a quadrant of the kiln near its exit using a bidirectional pressure probe and suction pyrometer. To accommodate the new bidirectional probe and gain access to the upper portion of the kiln, a lighter and stiffer positioning boom was designed. The kiln was directly fired using natural gas in a steady state mode. Results indicate strong vertical stratification of both velocity and temperature, with the highest values corresponding to the top of the kiln. Access restraints prevented the lower region of the kiln from being mapped. Horizontal variations in both temperature and velocity were insignificant. Operating conditions were varied by adjusting the amount of ambient air added to the front of the kiln. Increasing the flow of ambient air into the front of the kiln IMPLICATIONS Previous experimental work has shown that incinerator flows can be highly stratified in both temperature and chemical species. This latest work shows that the exit of a rotary kiln incinerator can also be highly stratified in velocity, and presents evidence that regions of reverse flow may exist. It is, therefore, important to consider the general velocity field when interpreting other measurements taken from the rotary kiln section of an incinerator. This is particularly important if single-point sampling is used to characterize the incineration process, so that stagnant areas and regions of reverse flow can be identified. This work presents a device and methodology for measuring velocities in high-temperature, particulate-laden turbulent flows. reduced the measured temperatures as expected, but did hot have as significant an effect on measured velocities. The quality of the results is examined by performing mass balances across the incinerator and by comparison to an existing numerical model. Both methods indicate that the experimental results are reasonable. BACKGROUND This study was performed at the Dow Chemical Company rotary kiln incinerator located in Plaquemine, Louisiana. This facility has been described by Cundy, et al. 1 Access to this kiln for experimental measurements is through an offaxis view port located at the back of the transition section between the exit of the rotary kiln incinerator and the entrance to the afterburner (see Figure 1). The refractory brick is 33 cm thick at this port, thus limiting boom movement.

Research paper thumbnail of Heat transfer between a rotating cylinder and a moist granular bed

International Journal of Heat and Mass Transfer, 1995

~_ model is developed which describes the heat transfer process between the rotating wall of a de... more ~_ model is developed which describes the heat transfer process between the rotating wall of a desorber and an adjacent bed of wet, granular solids. A heat-balance integral method is used. This solution includes the effects of water evaporation near the wall and a thermal contact resistance between the wall and the first layer of particles. The model allows for water evaporation before the bulk bed temperature reaches the saturation temperature of the water. Experimentally measured evaporation rates compare favorably to those predicted by the model. In particular, the water evaporation that occurs before the bulk bed temperature reaches the water saturation temperature is predicted.

Research paper thumbnail of Gas property effects on droplet atomiation and combustion in an air-assist atomier

Symposium (International) on Combustion, 1996

Nitrogen, Ar, and CO2 were used as the atomizing gas in an “air-assist” fuel nozzle to determine ... more Nitrogen, Ar, and CO2 were used as the atomizing gas in an “air-assist” fuel nozzle to determine the effect of these gases on droplet size, number density, and velocity in kerosene spray flames using a two-dimensional phase Doppler interferometer. Data were obtained with these atomizing gases and compared to the reference, air-assist case, since air is the most commonly used atomizing fluid. Comparisons were made between the gases on a mass and momentum flux basis. Both burning and nonburning sprays were investigated. The results show that under burning conditions, the presence of O2 in the air-atomized sprays influences the combustion process, reducing droplet size and increasing droplet velocity, especially in the region near the nozzle exit. Differences in droplet characteristics (size, velocity, and number density) are minimized in the momentum flux controlled cases, indicating the relevance of momentum flux over mass flux to control atomization. In both the nonburning and burning sprays, lighter gases more effectively atomized the fuel in comparison to the denser gases. Ar and CO2 produced larger, slower moving droplets than the air and N2 assisted cases under mass flux controlled conditions. The Ar and CO2 atomized flames were also observed to be significantly more luminous than air-atomized flames. These results suggest that the presence of O2 in the atomizing gas and gas density have significant effect on the atomization, mixing, and combustion processes, which, in turn, influence droplet lifetimes, flame structure, and emission levels.

Research paper thumbnail of Three-Dimensional Numerical Modeling of a Field-Scale Rotary Kiln Incinerator

Environmental Science & Technology, 1996

Research paper thumbnail of Heat Transfer Effects on Droplet Vaporization by Air Preheating

Journal of Heat Transfer, 1997

Research paper thumbnail of In Situ Velocity Measurements from an Industrial Rotary Kiln Incinerator

Journal of the Air & Waste Management Association, 1995

For the first time, velocities were measured inside a fieldscale rotary kiln incinerator. Combust... more For the first time, velocities were measured inside a fieldscale rotary kiln incinerator. Combustion gas velocities and temperatures were measured at multiple points across a quadrant of the kiln near its exit using a bidirectional pressure probe and suction pyrometer. To accommodate the new bidirectional probe and gain access to the upper portion of the kiln, a lighter and stiffer positioning boom was designed. The kiln was directly fired using natural gas in a steady state mode. Results indicate strong vertical stratification of both velocity and temperature, with the highest values corresponding to the top of the kiln. Access restraints prevented the lower region of the kiln from being mapped. Horizontal variations in both temperature and velocity were insignificant. Operating conditions were varied by adjusting the amount of ambient air added to the front of the kiln. Increasing the flow of ambient air into the front of the kiln IMPLICATIONS Previous experimental work has shown that incinerator flows can be highly stratified in both temperature and chemical species. This latest work shows that the exit of a rotary kiln incinerator can also be highly stratified in velocity, and presents evidence that regions of reverse flow may exist. It is, therefore, important to consider the general velocity field when interpreting other measurements taken from the rotary kiln section of an incinerator. This is particularly important if single-point sampling is used to characterize the incineration process, so that stagnant areas and regions of reverse flow can be identified. This work presents a device and methodology for measuring velocities in high-temperature, particulate-laden turbulent flows. reduced the measured temperatures as expected, but did hot have as significant an effect on measured velocities. The quality of the results is examined by performing mass balances across the incinerator and by comparison to an existing numerical model. Both methods indicate that the experimental results are reasonable. BACKGROUND This study was performed at the Dow Chemical Company rotary kiln incinerator located in Plaquemine, Louisiana. This facility has been described by Cundy, et al. 1 Access to this kiln for experimental measurements is through an offaxis view port located at the back of the transition section between the exit of the rotary kiln incinerator and the entrance to the afterburner (see Figure 1). The refractory brick is 33 cm thick at this port, thus limiting boom movement.

Research paper thumbnail of Heat transfer between a rotating cylinder and a moist granular bed

International Journal of Heat and Mass Transfer, 1995

~_ model is developed which describes the heat transfer process between the rotating wall of a de... more ~_ model is developed which describes the heat transfer process between the rotating wall of a desorber and an adjacent bed of wet, granular solids. A heat-balance integral method is used. This solution includes the effects of water evaporation near the wall and a thermal contact resistance between the wall and the first layer of particles. The model allows for water evaporation before the bulk bed temperature reaches the saturation temperature of the water. Experimentally measured evaporation rates compare favorably to those predicted by the model. In particular, the water evaporation that occurs before the bulk bed temperature reaches the water saturation temperature is predicted.

Research paper thumbnail of Gas property effects on droplet atomiation and combustion in an air-assist atomier

Symposium (International) on Combustion, 1996

Nitrogen, Ar, and CO2 were used as the atomizing gas in an “air-assist” fuel nozzle to determine ... more Nitrogen, Ar, and CO2 were used as the atomizing gas in an “air-assist” fuel nozzle to determine the effect of these gases on droplet size, number density, and velocity in kerosene spray flames using a two-dimensional phase Doppler interferometer. Data were obtained with these atomizing gases and compared to the reference, air-assist case, since air is the most commonly used atomizing fluid. Comparisons were made between the gases on a mass and momentum flux basis. Both burning and nonburning sprays were investigated. The results show that under burning conditions, the presence of O2 in the air-atomized sprays influences the combustion process, reducing droplet size and increasing droplet velocity, especially in the region near the nozzle exit. Differences in droplet characteristics (size, velocity, and number density) are minimized in the momentum flux controlled cases, indicating the relevance of momentum flux over mass flux to control atomization. In both the nonburning and burning sprays, lighter gases more effectively atomized the fuel in comparison to the denser gases. Ar and CO2 produced larger, slower moving droplets than the air and N2 assisted cases under mass flux controlled conditions. The Ar and CO2 atomized flames were also observed to be significantly more luminous than air-atomized flames. These results suggest that the presence of O2 in the atomizing gas and gas density have significant effect on the atomization, mixing, and combustion processes, which, in turn, influence droplet lifetimes, flame structure, and emission levels.

Research paper thumbnail of Three-Dimensional Numerical Modeling of a Field-Scale Rotary Kiln Incinerator

Environmental Science & Technology, 1996

Research paper thumbnail of Heat Transfer Effects on Droplet Vaporization by Air Preheating

Journal of Heat Transfer, 1997