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In the present study, LES (large-eddy simulation) is utilized to analyze lean-premixed propane-air flame stability in a backward-step combustor over a range of equivalence ratio. The artificially thickened flame approach coupled with a reduced reaction mechanism is incorporated for modeling the turbulence–combustion interactions at small scales. Simulation results are compared to high-speed PIV (particle...
This work aims to provide an accurate and simple model, predicting the time dependent devolatilization of woody biomass at conditions (Tgas < 2000 K) and particle sizes (<2 mm) relevant to suspension fired boilers. The zero dimensional model is developed from reference calculations with a one-dimensional heat transport model coupled with a drying and a devolatilization model. The model output...
The thermodynamic performance and optimization of a three-terminal quantum dot nano-device consisting of two capacitively coupled quantum dots connected to electron reservoirs in the Coulomb-blockade regime are investigated. Based on the master equation, the existing model with configuration A and a previously unreported model with configuration B of the device are studied and compared systematically...
The fast pyrolysis characteristics of Geodae-Uksae 1 were examined in a lab-scale bubbling fluidized bed reactor. First, raw material was examined thorough proximate and ultimate analyses. TGA (Thermogravimetric analysis) was carried out to determine the basic thermal degradation characteristics of the material. To study biocrude-oil yield and quality, 1 kg of Geodae-Uksae 1 was applied to the fluidized...
The paper presents an innovative and advanced MCC (mixture controlled combustion). The MCC model is coupled to the innovative mechanistically based 0D spray model presented in a companion paper [1] that provides inputs on fuel mass distribution. Advanced MCC model is embedded into a 2-zone combustion modeling framework. Advanced MCC predicts ROHR (Rate-Of-Heat-Release) as the combination of the premixed...
A compact desiccant-evaporative HMX (heat and mass exchanger) has been proposed by combining the benefits of the regenerative indirect evaporative cooling and the liquid desiccant dehumidification. In this design, the compact HMX was able to cool and dehumidify the product air simultaneously in a single unit. A computational model has been developed and validated using experimental data. The model...
M&V (Measurement and Verification) has become an indispensable process in various incentive EEDSM (energy efficiency and demand side management) programmes to accurately and reliably measure and verify the project performance in terms of energy and/or cost savings. Due to the uncertain nature of the unmeasurable savings, there is an inherent trade-off between the M&V accuracy and M&V cost...
This study presents a modified ejector expansion cycle with zeotropic mixtures (R290/R600a) for freezers, in which an ejector and a phase-separator are employed to enhance the cycle performance. Energetic and exergetic methods are used to theoretically investigate the system operating characteristics. In addition, comparative research among the modified cycle, conventional ejector expansion cycle...
In exploring new cobalt-free perovskite oxide cathodes for intermediate temperature SOFCs (solid oxide fuel cells), Sc and Nb co-doped SrFeO3-based perovskite, SSNF (SrSc0.175Nb0.025Fe0.8O3−δ) was synthesized. Powder X-ray diffraction, high resolution transmission electron microscopy and SAED (selected area electron diffraction) showed that SSNF crystallized in the tetragonal space group P4/mmm (#123)...
Wave energy is one of the most promising renewable energy for power generation. This research develops a novel power take-off methodology to surmount the problems associated with mooring, seawater corrosion and access for maintenance in conventional WEC (wave energy converters) with direct-driven linear generators. Its prototype consists of two bodies, the floating body acting as a buoy to extract...
The characteristics of the outwardly propagating premixed flames of stoichiometric mixtures of R134a/CH4/O2/N2 have been experimentally investigated in a constant volume combustion chamber. Three regimes of the expanding flames were categorized based on the flame behavior. In the typical regime, a conventional outwardly propagating spherical flame was observed. The laminar burning velocity was correlated...
High-resolution large-eddy simulation of the flow over a large wind farm (64 wind turbines) is performed using the HIGRAD/FIRETEC-WindBlade model, which is a high-performance computing wind turbine–atmosphere interaction model that uses the Lagrangian actuator line method to represent rotating turbine blades. These high-resolution large-eddy simulation results are used to parameterize the thrust and...
Graphitic carbon continues to dominate as the choice anode material in lithium-ion batteries despite its theoretical specific capacity of 372 mAhg−1. Tailored forms of graphite with higher practical capacities should, therefore, be of interest to the industry. This paper reports the production of a kish graphitic anode material from polyvinyl chloride by simultaneous carbonization of the polymer and...
In this study, biomass-based EL (ethyl levulinate) was evaluated as an additional fuel to biodiesel and diesel. Physical and chemical properties, including intersolubility, cold flow properties, spray evaporation, oxidation stability, anti-corrosive property, cleanliness, fire reliability and heating value of twelve different EL–biodiesel–diesel blends were analyzed. The results show that the fuel...
Based on one-dimensional steady analysis, a comprehensive theoretical model for analyzing the performance of TEGs (thermoelectric generators) is proposed, in which finite element method and integral-averaged Seebeck coefficient are employed to effectively consider the effects of temperature-dependence of thermoelectric materials and Thomson effect respectively. The optimal segments for each case are...
Energy generation by solar PV (photovoltaic) systems can be improved by incorporating tracking mechanisms, with the highest improvements resulting from 2-axis tracking. Peak energy generation levels (from PV collectors with 2-axis tracking) have been determined in this study, for locations in Nigeria. The spatial domain of interest was discretized into a grid of 1° latitude by 1° longitude cells....
The lifted dust particles from the ground and the dust particles existing in the air all can deposit on the surface of a PV (photovoltaic) module. These particles create a dust cover on the module front surface and reduce incident solar energy to the module glass surface. This study aimed to analysis a tilted PV module with dust deposition on its front surface. The optical-thermal modeling of the...
Enriched-air gasification was performed in fluidized bed reactors using the processed dairy manure which was mixed with sand bedding. The effects of temperature, modified equivalence ratio (ERm), and oxygen concentration on the gas products were investigated based on the statistical models using a bench-scale reactor in order to obtain empirical correlations. Then, the empirical equations were applied...
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