Library

2718 match your search

Much research has been devoted to reducing NOx and soot emissions simultaneously in diesel engines. The low temperature combustion (LTC) concept has the potential to reduce these emissions at the same time, but it has limitations to its commercialization. In-cylinder EGR stratification is another combustion concept meant to reduce both types of emissions simultaneously using non-uniform in-cylinder EGR gas distribution. The EGR stratification concept uses a locally high EGR region of the in-cylinder so that the emissions can be reduced without increasing the overall EGR rate. In this study,...
Particle image velocimetry was used in a low-speed wind tunnel to investigate the vortex structures of a slender reverse delta wing at various angles of attack and roll. This work investigates the characteristics of the vortices generated downstream in planes perpendicular to the freestream direction and their dependence on angles of attack and roll at a chord-based Reynolds number of Rec 3:82 105. The peak tangential velocities at>5 show a trend similar to a delta wing. A six-component balance was used to obtain the aerodynamic coefficients for a reverse delta wing as well as a delta wing...
The Oregon State University (OSU) High Temperature Test Facility (HTTF) is an integral experimental facility that will be constructed on the OSU campus in Corvallis, Oregon. The HTTF project was initiated, by the U.S. Nuclear Regulatory Commission (NRC), on September 5, 2008 as Task 4 of the 5-year High Temperature Gas Reactor Cooperative Agreement via NRC Contract 04-08-138. Until August, 2010, when a DOE contract was initiated to fund additional capabilities for the HTTF project, all of the funding support for the HTTF was provided by the NRC via a cooperative agreement. The U.S. Department...
This paper deals with the design and development of an innovative airship concept which is remotely-controlled and intended to be used for monitoring, surveillance, exploration and reconnaissance missions. Two potential solutions have been analyzed: the first consists of a double-hull configuration, characterized by the presence of a primary support structure connected by appropriated bindings to a couple of twin inflatable hulls. The second architecture is a soap-shaped exoskeleton configuration which features a single inflated section, incorporating two separate elements held internally by...
In order to optimize the balance between aerodynamics and air-cooling performances for a motorcycle, a simulation method of external flow around a vehicle has been developed. In this paper, steady-state flow calculations were performed using two types of turbulence models, the realizable k-ε and the SST k-ω , and two levels of mesh sizes of computational models and their results were compared. To validate the computational results, wind tunnel tests were conducted and CD, CL and mean velocity of flow passing through heat exchangers were measured. The computational results on drag coefficient...
Partially–premixed combustion occurs in many combustion devices of practical interest, such as gas–turbine combustors. Development of corresponding turbulent combustion models is important to improve the design of these systems in efforts to reduce fuel consumption and pollutant emissions. Turbulent lifted flames have been a canonical problem for testing models designed for partially–premixed turbulent combustion. In this paper we propose modifications to the coherent flame model (CFM) so that it can be brought to the simulation of partially-premixed combustion. For the primary premixed flame...
Simulations using CFD and chemical kinetics models have been applied to gain a better understanding of the effect of the recirculated gases on the autoignition process during cold starting of a direct injection diesel engine. The cranking gases recirculated (CGR) contain fuel vapor and partial oxidation products which affect the autoignition process in different ways. Some hydrocarbons (HCs) species enhance the reaction rates and reduce ignition delay. Meanwhile other HCs species and the partial oxidation products of the autoignition process have an opposing effect. The simulation covered a...

Pages