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Large-scale emergency or off-grid power generation is typically achieved through diesel or natural gas generators. To meet governmental emission requirements, emission control systems (ECS) are required. In operation, effective control over the generator’s acoustic emission is also necessary, and can be accomplished within the ECS system. Plug flow mufflers are commonly used, as they provide a sufficient level of noise attenuation in a compact structure. The key design parameter is the transmission loss of the muffler, as this dictates the level of attenuation at a given frequency. This work implements an analytically decoupled solution, using multiple perforate impedance models, through the transfer matrix method (TMM) to predict the transmission loss based on the muffler geometry. An equivalent finite element model is implemented for numerical simulation. The analytical results and numerical results are then evaluated against experimental data from literature.

Due to the strong motivation to reduce costs and increase performances of stationary diesel after-treatment systems, computational modeling has become a necessary step in system design and improvement. A unique mixing duct with significant changes in scale and strong flow curvature was evaluated for its potential to improve flow distribution across the SCR catalyst inlet face. The flow dynamics were investigated with a steady three-dimensional turbulence model and detailed chemistry was studied separately using a one-dimensional channel reactive flow model. Aqueous urea injection was modeled using Discrete Phase Modeling. The mixing duct performance relative to reactor dimensions and engine loads is discussed. A total of three geometries were evaluated using a Uniformity Index of the ammonia-to-NOx feed ratio. It was found that a higher mixing duct height to inlet diameter ratio yielded better mixing.

The internal force of a variable displacement vane pump has been studied in detail with ten Computational Fluid Dynamics (CFD) cases with different pump speed and eccentricity. The internal moment increases considerably with faster pump speed, and at higher speeds, it can exceed the moment due to the spring force causing the slide to regulate at much lower pump discharge pressure. At low pump speeds, the effect of eccentricity is minimal. The maximum value of internal moment is expected to occur at high speeds and maximum eccentricity. There are two reasons for variation of internal moment with pump speed and eccentricity: (a) the variation of effective pressurized area of the slide changes with pump speed and (b) higher pressure in the blind ports at higher eccentricity. This study provides insight into pump forces during high-speed operation of vane pumps.

Flow near a spark plug is important for early flame kernel development (EFKD) and combustion efficiency. Velocity data have been measured by a laser Doppler velocimetry (LDV) for three different positions near a spark plug within a ported single cylinder optical spark ignition (SI) engine with a heart-shaped combustion chamber and a compression ratio of 8.9. LDV measurements have been performed under the wide-open motored conditions with an engine speed of 1,000 rpm conditions and maximum data collection rates of 22 kHz per channel. This work examines the mean and turbulence flow fields as interpreted through ensemble, cyclic, discrete wavelet transformation (DWT) analysis and the energy cascade as analyzed through continuous wavelet transformation (CWT) for flows near a spark plug.

A computational investigation of engine flow in an optical water analog engine has been carried out using KIVA. Three cases (20 RPM, 40 RPM and 60 RPM) are examined and discussed. From the comparison of the three different cases, there are obvious cyclic variations for different piston velocities. The discrepancies in the cases demonstrate that the transition to turbulence occurs at the lower RPM (e.g. 20 RPM) while fully developed turbulence seems to start at the higher RPMs (e.g. 40 and 60 RPM). These, therefore, suggest that 2D PIV used in previous measurement is valid at lower RPM because the measurement actually measures the jet or the turbulence transition from jet, but 3D stereoscopic PIV is certainly better and necessary at higher RPM due to the 3D character of the turbulence. The work will assist in the design of new experiments, and provide direction for improving modelling techniques.