Broadband shock-associated noise is a component of jet noise generated by supersonic jets operating offdesign. It is characterized by multiple broadband peaks and dominates the total noise at large angles to the jet downstream axis. A new model is introduced for the prediction of broadband shock-associated noise that uses the solution of the Reynolds-averaged Navier-Stokes equations. The noise model is an acoustic analogy based on the linearized Euler equations. The equivalent source terms depend on the product of the fluctuations associated with the jet's shock-cell structure and the turbulent velocity fluctuations in the jet shear layer. The former are deterministic and are obtained from the Reynolds-averaged Navier-Stokes solution. A statistical model is introduced to describe the properties of the turbulence. Only the geometry and operating conditions of the nozzle need to be known to make noise predictions. This overcomes the limitations and empiricism present in previous broadband shock-associated noise models. Results for various axisymmetric circular nozzles and a rectangular nozzle operating at various conditions are compared with experimental data to validate the model.

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The effect of co-firing of biomass fuels with oil shale on combustion was investigated. Thermogravimetric analysis and differential scanning calorimetry were the tools used to perform the investigation. Since the combustion of biomass is highly exothermic, biomass fuels can serve as an appropriate fuel feedstock. Biomass fuels producing much volatile matter and containing less cellulose are good candidates for co-firing with oil shale. The biomass samples used in the study were hazelnut shell, wheat bran, poplar, and miscanthus. Co-firing of biomass/oil shale blends was performed using different biomass ratios (10, 20 and 50% by weight).

Gasification is a process through which solid and liquid carbonaceous materials are converted to a combustible product gas consisting of a mixture of CO, CO 2 , H 2 , and CH 4 (and N 2 if air is used as a source of oxygen). The product gas can be combusted to provide energy or can be used for a variety of industrial applications. Gasification is a potentially cleaner and more efficient means of energy production than combustion of solid fuels. While gasification has been extensively researched, specifically coal gasification and to a lesser extent biomass gasification, a niche application of gasifying byproducts from the cattle rendering and meatpacking industries is gaining interest. Because of recent outbreaks of mad cow disease in Canada and the United States, regulations on the use of specified risk material (SRM), meat and bone meal, and entire carcasses are becoming more stringent in Canada and in the future are expected to become more stringent in the United States as well. One possible disposal option for these materials is gasification. In this study, four byproduct materials from the cattle rendering and meatpacking industries were gasified in a bench-scale gasification unit at Penn State's Energy Institute. The feed materials included meat and bone meal, cow carcasses, and two types of SRMs. The feed samples were gasified at 1000 °C with nitrogen and steam carrier gasses. The composition of the product gas produced during the gasification reaction was analyzed using gas chromatography. A material balance of the reaction was conducted to assess reliability of the results. Gas production, hydrogen yields, other combustible gas yields, and energy densities show that gasification can potentially serve as a means of carcass and SRM disposal and energy production in the cattle rendering and meatpacking industries.

The objective of this work was to investigate the effect of the particle size distribution (PSD) of mineral matter in coal on the particle size distribution of ash produced during firing of two coals in pulverized coal and coal-water slurry forms. The coals used in this work were Beulah (North Dakota) lignite and Elk Creek (West Virginia) high volatile A bituminous coal. Combustion experiments were performed in a pilot-scale 316 MJ/h down-fired unit with 20% excess air. The dominant mechanism of ash formation in the Beulah pulverized coal was fragmentation of mineral particles, specifically pyrite, resulting in a finer ash particle size distribution than that of the origiml ' mineral matter (62% reduction in dw of mineral matter). By contrast, the main mechanism for determining the ash particle size in the Beulah coal-water slurry fuel (CWSF) was coalescence and agglomeration of the inorganic portion of the fuel (225% increase in dm of mineral matter). The size distribution and occurrence of inorganic matter in the fuels were the most important factors in determining ash size. Differences in pyrite PSD and occurrence between the two fuels were significant in determining the dominant mechanism for aiilh formation. The CWSF preparation process resulted in a significant reduction in the pyrite PSD and removal of organically bound sodium from the CWSF. The reduction in sodium in the CWSF did not significantly reduce the coalescence of ash particles during combustion. The PSDs of ashes from both pulverized and slurried Elk Creek coal are coarser than the original mineral matter, due to coalescence of inherent aluminosilicates and silicates during combustion. The particle size of the Elk Creek coal-water slurry fuel ash is slightly coarser than that from pulverized coal, due to the larger agglomerate formed upon atomization of the Elk Creek slurry. Atomization quality was the most important factor in determining the particle size of the ash. Subsequent papers will discuss the chemical interactions among the inorganic components during combustion of these fuels.

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