Papers by Keyword: CFD Model

Abstract: This paper presents a predictive investigation using CFD techniques focusing on the tradeoff between steady-state airflow considerations and unsteady transient pressure wave tuning of a single cylinder IC engine. An axisymmetric CFD model has been developed to initially examine the steady-state flow characteristics generated by different inlet entry radii. This has then been further developed to incorporate the unsteady, transient pressure wave effects caused by the motion of inlet valve and piston. Detailed simulation results, which are validated against experimental data provided by Group Lotus plc, are reported here and quantitative conclusions are drawn for maximising airflow in future inlet manifold design.

Abstract: This paper presents a predictive investigation using Computational Fluid Dynamic (CFD) techniques focusing on the study of contamination that occurs between different products in an oil pipeline under normal operating conditions. The use of CFD techniques yields detailed flow conditions including the velocity fields, phase distribution and interface evolution, which can provide valuable information to the oil industry especially in the distribution of oil products. The Volume of Fluid (VOF) model is used in this project in a pipe with two fluids. Simulation results show the interface evolution between the two fluids and how it is affected by properties such as viscosity ratio and pressure difference. Operational data from the Nigerian National Petroleum Corporation was obtained to validate the results from the simulations.

Abstract: The proportional flow control valve is not only one of the key competent of vane damp,but also the execution unit of shock absorber damping force's regulation .The proportional flow control valves self-designed will combine the structural design of proportional control valve and crate CFD model . The thesis analyzes its distribution of flow field by CFD and acquires experimental validation .It analyzes dynamic characteristics and determine the relationship of flow and opening and drive current. The proportional control valve test verifies the correctness, finally. It is basis for analyzing of damping characteristics about vane damp, which can be used other proportional control valve CFD study.

Abstract: A 2 D CFD model was established to simulate sawdust gasification in an entrained flow gasifier using Ansys Fluent software. Syngas composition, syngas yield and syngas LHV were evaluated. The simulated syngas compositions were in agreement with the experiment results. The relative errors of syngas yield and LHV varied in the ranges of 2-15% and 1-9%, respectively. The results showed that the numerical model established in this study can be applied to simulate biomass gasification in entrained flow gasifier.

Abstract: Pultrusion process is gaining increasing attention in several sectors, due to the high productivity and quality achievable. Recent researches highlighted the influence of the pulling force on the quality of pultruded products. In this paper a pulling force model, accounting for compacting, viscous, and frictional effects in a conventional pultrusion process has been implemented. The model is based on the combination of an impregnation, a thermochemical, and a frictional sub-models. Obtained outcomes evidenced, for the considered case,adominant role of the viscous drag.

Abstract: In recent years, remarkable interest has been focused on the Friction Stir Welding (FSW) process, by academic as well as industrial research groups. Conceptually, the FSW process is quite simple: a non-consumable rotating tool is plunged between the adjoining edges of the parts to be welded and moved along the desired weld line. Frictional and viscous heat generation increases the work piece temperature, softening the processing material and forcing it to flow around the pin. Although FSW has been effectively applied in welding of several materials, such as copper, steel, magnesium, and titanium, considerable attention is still focused on aluminum welding, in particular for transport applications. Recent literature clearly evidenced microstructural variations in the stir zone, imputable to continuous dynamic recrystallization phenomena, leading to the formation of a finer equiaxed grains. Moreover, depending on the specific alloy, thermal cycles can induce coarsening or dissolution of precipitates in the thermo-mechanically affected zone (TMAZ) and in the heat affected zone (HAZ). The influence of the aforementioned microstructural aspects on mechanical properties and formability of FSWed assemblies is also well recognized. The aim of this paper is to numerically and experimentally investigate the influence of process parameters, namely rotating speed and welding speed, on microstructural aspects in AA2024-T3 friction stir butt welds. A three-dimensional Computational Fluid Dynamic (CFD) model has been implemented to simulate the process. A viscoplastic material model, based on Wright and Sheppard modification of the constitutive model initially proposed by Sellars and Tegart has been implemented in the commercial package ANSYS CFX, considering an Eulerian framework. Tool-workpiece interaction has been modeled assuming partial sticking/sliding condition, and incorporating both frictional and viscous contributions to the heat generation. Microstructural aspects have been numerically predicted using the Zenner-Holloman parameter and experimentally measured by means of conventional metallographic techniques. Satisfactory agreement has been found between simulated and experimental results. The influence of process parameters on mechanical properties has also been highlighted.

Abstract: The numerical simulation in fluid mechanics has large application in chemical engineering. The objective of the present work is the analyze of a computational model for the fluid dynamics behaviour of a bubble column of the geometry cylindrical non regular with multiphase mixture. Experimental data and CFD results of the hydrodynamics of gaseous and liquid phases have been compared. Five different diameters of bubbles have been used in the CFD simulations. The comparisons between CFD simulations and experimental data show that the Eulerian-Eulerian approach provides a computational model that represents the process satisfactorily.

Abstract: The surface roughness plays an important role in elastohydrodynamic lubrication (EHL). To improve the lubrication system the flow behavior and lubrication mechanism must be understood, especially in the thin film classification. The effects of surface roughness in the EHL problem are complicated and difficult to measure by experiment. Therefore numerical simulation using the computational fluid dynamic (CFD) approach is proposed in this research. The CFD model developed has taken the arbitrary surface roughness into consideration, and has been used to predict the characteristics of fluid flow, such as the pressure distribution, the minimal film thickness and the shear stress. The cylinder is considered to be under elastic deformation according to the theory of Hertzian contact and the surface of cylinder is defined to have an arbitrary roughness. The simulation results show that the surface roughness has significant effects on the pressure profile and shear stress, especially in the case of pure rolling, where the two parameters in the rough surface case show large fluctuations that are much higher than the corresponding smooth surface case.

Abstract: This paper optimized the design of the cooling fans of a light-duty diesel engine through numerical simulation. Using Fluent as a platform, a detailed Computational fluid dynamics (CFD) model was developed to simulate both the aerodynamic and the acoustics performance. The model developed was validated against experimental data obtained in this research. The validated model was then used to optimize the design of the cooling fan aiming to minimize the operation noise. With the guarantee of cooling performances, the aerodynamic noise of the two fans has been successfully reduced.