Current Issue : January - March Volume : 2015 Issue Number : 1 Articles : 5 Articles
Structural shape deformation, in its conventional way, includes applying forces to a fixed-compliance structure to deform it to\ncertain shapes. Rather than addressing shape control in the established way (applying forces to elastically or plastically deform\na structure), this work studies the use of shape morphing, which involves combining applied forces and local modulus changes.\nSpecifically in this paper, a simply supported elastic beamthat can exhibit variable compliance behavior is selected as the model. This\nstudy focuses on the forward approach ofmorphing, that is, determining possible beamshapes due to the applied force andmodulus\nvariability Thegoal is to incorporate variable-modulusmaterials into a structure model and utilize the controllable modulus change\nto quantify the morphing of the structure with limited actuator numbers, locations, and force levels. The resulting morphed shapes\nare quantified in terms of various characteristic parameters. The study demonstrates that a larger, and in some cases nonintuitive,\nspace of shapes becomes possible when modulus change is utilized, for the same set of applied forces....
In oil and gas drilling operations, predictions of pressure losses and cuttings concentration in the annulus are very complex due\nto the combination of interacting drilling parameters. Past studies have proposed many empirical correlations to estimate pressure\nlosses and cuttings concentration.However, these developed correlations are limited to their experimental data range and setup, and\nhence, they cannot be applicable to all cases. CFD methods have the advantages of handling complex multiphase flow problems, as\nwell as, an unlimited number of physical and operational conditions. The present study employs the inhomogeneous (Eulerian-\nEulerian) model to simulate a two-phase solid-fluid flow and predict pressure losses and cuttings concentration in eccentric\nhorizontal annuli as a function of varying drilling parameters: fluid velocity, diameter ratio (ratio of inner pipe diameter to outer\npipe diameter), inner pipe rotation speed, and fluid type. Experimental data for pressure losses and cuttings concentration from\nprevious literature compared very well with simulation data, confirming the validity of the current model. The study shows how\nreliable CFD methods can replicate the actual, yet complex oil and gas drilling operations....
Very high temperature reactor (VHTR) designs offer promising performance characteristics; they can provide sustainable energy,\nimproved proliferation resistance, inherent safety, and high temperature heat supply. These designs also promise operation to\nhigh burnup and large margins to fuel failure with excellent fission product retention via the TRISO fuel design. The pebble bed\nreactor (PBR) is a design of gas cooled high temperature reactor, candidate for Generation IV of Nuclear Energy Systems. This\npaper describes the features of a detailed geometric computational model for PBR whole core analysis using the MCNPX code.\nThe validation of the model was carried out using the HTR-10 benchmark. Results were compared with experimental data and\ncalculations of other authors. In addition, sensitivity analysis of several parameters that could have influenced the results and the\naccuracy of model was made...
An optimization technique for combined processes of deep-drawing and ironing has been created in order to improve the total\nprocess time and cost in manufacturing procedures of axisymmetric components. The initial solution is optimized by means of an\nalgorithm that minimizes the total time of the global process, based on relationship between lengths, diameters, and velocities of\neach stage of a multistage process and subject to constraints related to the drawing ratio.The enhanced solution offers a significant\nreduction in time and cost of the global process. The final results, applied to three cases, are compared with experimental results,\nshowing the accuracy of the complete solution....
Measurements acquired at the rotor exit plane illuminate the interaction of the rotor with the upstream vane row and the\ndownstream vane row.The relative phase of the upstream and downstream vane rows is adjusted using vane clocking so that the\neffect of the upstreampropagating potential field fromthe downstream stator can be distinguished fromthe effects associated with\nthewakes shed fromtheupstreamstator.Unsteady absoluteflowangle informationshows that thedownstreampotentialfieldcauses\nthe absolute flowangle to increase in the vicinity of the downstreamstator leading edge.Thepresence of Stator 1wake is also detected\nat this measurement plane using unsteady total pressure data. The rotor wakes are measured at different circumferential locations\nacross the vane passage, and the influence of Stator 1 wake on the suction side of the rotor wake is evident. Also, the influence of\nthe downstreamstator is detected on the pressure side of the rotor wake for a particular clocking configuration. Understanding the\nrole of the surrounding vane rows on rotor wake development will lead to improved comparison between experimental data and\nresults from computational models....
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