Library

2844 match your search

The economic recession, the environmental impact as well as the continuous fossil fuel consumption encourage actions that focus on saving energy. In the vessels sector, one of the main objectives has always been to reach a hydro-dynamically optimum hull which gave the desired speed with minimum power.Hydrodynamic drag is basically divided into two parts: a) the friction between the water and the hull,and b) the wave generation due to the free-surface air-water. Presented in this paper, is the research which evaluates the possibility of friction-drag reduction by means of the coat of special...
Background: Wall shear stress (SS) plays an important role in the initiation and proliferation of coronary atherosclerosis, especially for bifurcations. Stenting in the coronary artery will cause many different changes in velocity, flow, cross-sectional area, and especially the wall SS. However, it is still unknown how much wall SS distribution varies with stenting in coronary bifurcation. Objective: The purpose of this study was to investigate the magnitude and distribution of wall SS after the classical crush stenting for bifurcation lesions. Methods: Eleven patients with true coronary...
Jet ignition and direct fuel injection are potential enablers of higher efficiency, cleaner Internal Combustion Engines (ICE). Very lean mixtures of gaseous fuels could be burned with pollutants formation below Euro 6 levels (in the ultra-lean mode), efficiencies approaching 50% full load and small efficiency penalties when operating part load. The lean burn Direct Injection Jet Ignition (DI-JI) ICE uses a fuel injection and mixture ignition system comprising one main chamber direct fuel injector and one small size jet ignition pre-chamber per engine cylinder. The jet ignition pre-chamber is...
This paper presents recent advances in the development and integral validation of a two-phase Computational Fluid Dynamics (CFD) computer model (CFDBWR) that allows the detailed analysis of the two-phase flow and heat transfer phenomena in Boiling Water Reactor (BWR) fuel bundles. The CFD-BWR code is being developed as a customized module built on the foundation of the commercial CFD-code STAR-CD which provides general two-phase flow modeling capabilities.
This paper presents the efforts done by Volvo 3P, through a partnership with ThermoAnalytics Inc, to develop transient thermal simulation methodologies of the under hood of a truck. The verification process for the hot spots analysis currently in use at Volvo 3P is described and the key transient situations for the hot spots analysis are identified: hot shutdown, DPF regeneration and long drive cycle, are currently only covered by physical testing late in the project, contrary to steady-state operating conditions that are already managed through simulations in the early stage of the...
An advanced simulator is newly developed to predict fly ash modification behavior by direct injection of Ca fine particles in coal combustion furnaces. The Ca fine particles are a by-product of cement manufacturing process. This simulator is built on the coal combustion/gasification module based on the commercial Computational Fluid Dynamics (CFD) software of STAR-CD V3.26. Regarding the fly ash modification reaction model, it is based on the solid particle coagulation model. We improve this coagulation model to apply the fly ash modification reaction. The parameters of this particle...
The geometrical design of the airbox for an internal combustion engine has a significant effect on the pressure loss in the entire inlet tract. Due to the location of the airbox, its size and shape is usually limited as a result of the proximity to other under-bonnet features.The shape is also limited by manufacturing, assembly and NVH considerations. The complexity of the unsteady flow through the airbox and the constraints placed upon it by the available volume in the under-bonnet area make this a challenging design task. This paper reviews the current thinking on methods used to optimize...
Analysis of drag and lift forces and evaluation of scour around bridge structures are necessary to assess risk of bridge failure during storms and floods. Simulation of scour-hole formation under the bridge deck and around the bridge piers, due to sediment entrainment and transport caused by flooding flow conditions, is of significant interest to computational fluid dynamics (CFD) and hydraulics researchers. This study is focused on simulation of 3-D open channel turbulent flow over an inundated bridge deck to obtain the final shape and size of the scour-hole. This 3-D study extends the...
In La Solana in Spain a solar power plant with a peak output of about 6.5 MW is in operation. Solar inverters are used to transform the current into line frequency. To protect the inverters from atmospheric influence, the inverters are placed in small buildings. During the transformation process there is a power loss, which is released in heat form. To cool down the electric devices sufficiently and ensure a smooth operation, a earth heat exchanger system was constructed and built by TinniT Technologies. This cooling system is using the fact, that the earth temperature in only a few meters (...
The need for repair rather than replace of gas turbine components is becoming increasingly important to operators in today’s economic climate. The use of commercially available numerical analysis software, computational fluid dynamics (CFD) and finite element (FE) have become well established within Wood Group Light Industrial Turbines Ltd. They have allowed the business to be extremely competitive by being able to rapidly respond to a customers request for a repair which may involve a fluid structure interaction and/or conjugate heat transfer analysis. The software has also been used to...

Pages