Liquid composite molding process is a cost efficient manufacturing process for fiber reinforced composites. Despite all its advantages, the process results in defective parts having micro and macro voids resulting from the uneven infusion of the resin and variations in the internal geometry of the reinforcements. Numerical modeling and simulations are extensively used for the process characterization and optimization. Here we present a numerical study to assess the void formation as a result of the permeability variation at a macro scale. Resin flow is simulated through a porous medium with two distinct regions of different permeabilities. The results show a stark difference in the flow front advancement in the two regions, creating an uneven flow. The size and formation of the void depends on the difference in the permeabilities of the two regions.
The dynamic stability of a wing carrying an engine, and subjected to a lateral follower thrust force is investigated. In addition, quasisteady aerodynamic forces are introduced along the wing. The wing is considered as a cantilever tapered beam, made of a viscoelastic material governed by KelvinVoigt model. The mass and inertia of the engine are modeled in order to achieve more realistic behavior of the engine upon divergence and flutter characteristics of the system. Moreover, the generalized function theory is used to more accurately consider the contribution of the mass and its follower force in the governing equations. The governing equations of motion are derived through the Extended Hamilton's Principle. The resulting partial differential equations are solved by Galerkin's Method along with the classical flutter investigation approach. Parametric studies highlighting the sensitivity of the engine location on the flutter speed and flutter frequency are reported.
In this paper, we invest the energyabsorbing features of a lightweight aluminum honeycomb holding surrounded carbon fiber reinforced plastic (CFRP) tubes. The initial test has been done for a plain aluminum honeycomb in order to illustrate its specific energy absorption (SEA) and usual failure mechanisms. Moreover, tests are then conducted on honeycomb cores reinforced with increasing numbers of composite tubes in order to establish the influence of varying the density of the tubular array on the measured SEA.
The effect of a bluffbody, close/open base cone, on turbulent propaneair premixedflames was investigated computationally. The CFD model coupled with energy and species was developed using ANSYSFLUENT workbench associated with a reduced builtin kinetic mechanism of PropaneAir. The effect of the heat losses by radiation on the flame stability was examined as well. It was established from previously conducted experiments that turbulent flames were affected by different factors that characterized the stabilizer structure of the flame and its properties. Results were obtained and compared to demonstrate a modeling approach of the stability of turbulent flames in the existence of a conical bluffbody with closeversus openbase. The temperature profiles were found to examine the effect of the flame radiation loses and validate the computational results with the experimental results. In addition, the velocity profiles were obtained to compare the recirculation region as a fundamental key factor for flame sustainability
Strategic planning for water and electricity is one of the most important targets for any government around the world. Understanding potential changes in the wholesale pricing of electricity and water and its mechanism become a necessity for both supply and demand sides. This research focuses on addressing several price mechanisms that harmonize the interrelated sectors of water and electricity with a target to minimize the true costs for power and water. Moreover, it highlights the current Abu Dhabi electrical and water price allocation.
Chemical looping Reforming (CLR) is a process of transforming the fossil fuel into a clean energy carrier, hydrogen (H2), while capturing the carbon dioxide (CO2) and minimizing the NOx emissions. In the current study, suitable OCs are identified by performing thermodynamic analysis and the best OCs are used in the system level study. The system level model was developed in Aspen Plus. A comprehensive economic assessment was also carried out to calculate the price of H2 production. The results indicate that OC with the base metal as iron (Fe) is the most suitable candidate. The thermodynamic model shows that the global efficiency (H2 and power production) of the plant, in the case of Fe and W oxides is 74.3% and 71.7%, respectively. The economic assessment indicates that the cost of H2 production is $1.64 /kg. This paper also presents the computational fluid dynamic analysis of a bubbling fluidized bed reactor.
The growing concerns about global warming from fossil fuels has led to increased interest in developing efficient CO2 capture technologies. CO2 capture from fossil fuel powered plants could result in significant emissions reduction. Though available CO2 capture technologies are becoming quite mature, they result in significant energy penalty and are currently costly. Chemical looping combustion (CLC) is a relatively new method viewed as a promising CO2 capture technique that could make CO2 capture economically feasible. CLC employs an oxygen carrier circulated between two reactors for combustion of fuels using a redox reaction loop. In this study, a CLC system using solar source for heating the oxygen carrier needed for the endothermic reaction is numerical analyzed. In the study, various scenarios of solar heating are examined and the system performances under the examined scenarios are evaluated. The cost of electricity for the system was also examined.
The tensile behavior of graphene foam was investigated in this paper. The relationship between graphene foam density and Young's modulus and tensile strength was given and the deformation mechanism and fracture mode is studied. In addition, image processing technique was introduced to analyze the surface deformation of graphene foam under tensile loading.
Conventional rock physics analyses are crucial in the field of oil and gas as they allow for the characterization and management of reservoir production. Digital Rock Physics (DRP) is an emerging field that helps determine rock properties from images. The main workflow of DRP involves three steps? image acquisition, image segmentation and numerical computation. In this work, a systematic study was conducted where different segmentation techniques were applied to determine their effect on porosity and permeability values of a carbonate rock sample.
Studies of tectonic evolution and the distribution characteristics play an directive role in the exploration and development as well as reserves prediction in this area. Based on the data from predecessors' research, and the tectonic setting, the tectonic evolution in Jiyang depression in general could be divided into the following three stages: the extrusion deformation stage in Paleozoic? faultdepression stage in Mesozoic? fracture extensional tectonic movement stage in Cenozoic. It is summarized that the distribution law of formation is partition within depression, zoning in sag? Cenozoic formation development has significant differences? Inside belt and outside belt, formation in Paleogene develops significantly different in sags. Through the studies of the formation characteristics of the main oilrich sags, namely Dongying sag and Zhanhua sag, the main enrichment of oil and gas layers and zones are concluded, providing a guidance for further development.
