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In this paper an improved finite volume scheme to discretize diffusive flux on a non-orthogonal mesh is proposed. This approach, based on an iterative technique initially suggested by Khosla and known as deferred correction, has been intensively utilized by Muzaferija and later Fergizer and Peric to deal with the non-orthogonality of the control volumes. Using a more suitable decomposition of the normal gradient, our scheme gives accurate solutions in geometries where the basic idea of Muzaferija fails. First the performances of both schemes are compared for a Poisson problem solved in...
One of the major issues coming out from low temperature fuel cells concerns the production of water vapor as a chemical reaction (between hydrogen and oxygen) by-product and its consequent condensation (at certain operating conditions), determining the presence of an amount of liquid water affecting the performance of the fuel cell stack: the production and the quantity of liquid water are strictly influenced by boundaries and power output conditions. Starting from this point, this work focuses on collecting all the required information available in literature and defining a suitable CFD...
The influence of environmental changes on underhood and underbody components of a vehicle is an important issue in new vehicle design as increased engine power, cabin comfort demands and package space limitations create an increasingly difficult problem to solve. Sufficient airflow needs to be available for adequate cooling of the underhood components. The amount of air mass flow depends on the underhood geometry details: positioning and size of the grilles, fan operation, and the positioning of the other underhood components. This paper describes a prediction methodology that significantly...
A 2200 cc engine head for marine applications has been analysed and optimized by means of decoupled CFD and FEM simulations in order to assess the fatigue strength of the component. The fluid distribution within the cooling jacket was extensively analysed and improved in previous works, in order to enhance the performance of the coolant galleries. A simplified methodology was then proposed in order to estimate the thermo-mechanical behaviour of the head under actual engine operation. As a consequence of the many complex phenomena involved, an improved approach is presented in this paper,...
Hypoplastic left heart syndrome (HLHS) is a complex cardiac malformation in neonates suffering from congenital heart disease and occurs in 1 per 5000 births. HLHS is uniformly fatal within the first hours or days after birth as the severely malformed anatomies of the left ventricle, mitral and aortic valves, and ascending aorta are not compatible with life. The regularly implemented treatment, the Norwood operation, is a complex open heart procedure that attempts to establish univentricular circulation by removing the atrial septum (communicating the right and left ventricle), reconstructing...
The air-cooled engine surfaces are generally provided with extended surfaces of high conducting materials called fins for enhanced heat transfer. One way to increase the rate of heat transfer is by increasing the fins surface area. However, increase in fin length introduces undesirable vibrations of the fins, which in turn radiate annoying high frequency noise. With the demand of quieter engines increasing, the vehicle manufacturers follow counter measures to minimize the fin vibrations. One trend in the two-wheeler industry is to put rubber dampers between the fins. These rubber dampers...
The differential equation for dilute species transport next to a planar interface within the hydrodynamic boundary layer is transformed into a differential equation for the diffusion boundary layer. This differential equation contains two coefficients, which depend explicitly on the concentration profile. We show that these coefficients can be taken as identical constants, in a number of limiting cases. Using these constants, we show that this equation reproduces very well the temporal and spatial profile of the diffusion boundary layer determined from numerical simulations in some more...
One of the common causes of premature tube failure in fired tube boilers - technically described as film boiling - is overheating of the tubes caused by steam blanketing. Current literature contains a significant amount of information on this problem, but not much in the way of definitive guidance for avoiding the problem. General “rules of thumb” are available for identifying the heat flux limit required to avoid the problem as in Martens et al . Unfortunately, the values presented by different sources are often in disagreement. This paper will look at a sulfur recovery unit (SRU) Claus...
This paper investigates the first part of a two-stage methodology for the detailed fully coupled modelling of nanoparticle formation in turbulent reacting flows. We use a projected fields (PF) method to approximate the joint composition probability density function (PDF) transport equation that describes the evolution of the nanoparticles. The method combines detailed chemistry and the method of moments with interpolative closure (MoMIC) population balance model in a commercial computational fluid dynamics (CFD) code. We show details of the implementation and present an extensive set of...
The effects of a typical glaze ice accretion shape on the performance of the M2129 S-duct inlets are computationally investigated using the steady-state RANS solution. The glaze ice accreted on the inlet lip causes a significant degradation in the inlet performance, and the degradation is enhanced as free-stream Mach numbers increase. With increasing freestream Mach numbers from M =0.13 to 0.85, total pressure recovery decreases from 0.985 to 0.61. And the level of the mass flow rate with the glaze ice accretion is 73 percent of that in the ice-free condition at M =0.13; however, it decreases...

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