NOPR Collection:

Flow through S.I. engine air intake system using CFD at part throttle and full throttle

Thu, 01 Apr 2004 00:00:00 GMT

Title: Flow through S.I. engine air intake system using CFD at part throttle and full throttle Authors: Kumar, J Suresh; Ganesan, V Abstract: The objective of present study is to predict and analyze the flow through the SI engine air intake system using Computational Fluid Dynamics (CFD) and to validate the prediction by experimental data. Three-dimensional model of air intake system was analyzed by using the commercially available FLUENT software. The mesh was generated using the Tethybrid scheme which includes primarily of tetrahedral mesh elements but may include hexahedral, pyramidal and wedge elements. The pressure boundary conditions were used to define the fluid pressure at the inlet and outlet of Air Intake System. In the present study, the CFD code was validated by the experimental work. Experimental data was generated at one bar outlet pressure for the part throttle and full throttle conditions. The CFD plots give informative pictures of the flow field, which will help the designer to understand the effect of various components of Air Intake System. The predicted airflow rate shows good agreement with the experimental results. The results indicate that the CFD model can be used as a tool to understand the effect of various parts of air intake system for optimization. This in effect will reduce the number of experiments to be carried out for arriving at final optimized system. Page(s): 93-99

Investigation of the flow field in the various regions of intake manifold of a S.I. engine

Thu, 01 Apr 2004 00:00:00 GMT

Title: Investigation of the flow field in the various regions of intake manifold of a S.I. engine Authors: Kale, S C; Ganesan, V Abstract: The main objective of the present worlds to make a computational study of steady flow through intake manifold, port, valve and valve seat of a S.I. engine for various valve lifts. Three-dimensional flow within the manifold, port and valve has been simulated using the computational fluid dynamics (CFD) using the code STAR-CD. Flow field details in the identified regions in the manifold for the various valve lifts have been predicted. Analysis has been carried out for runners 1 and 3 at three different valve lifts for various speeds at wide-open throttle condition. A trimmed cell (adjust and cut process based on an underlying structured grid) has been adopted for meshing the geometries. Flow has been simulated by solving governing equations, viz., conservation of mass and momentum using the SIMPLE-algorithm. Turbulence has been modeled by high Reynolds number version of k-ɛ: model. Mass flow rate measurements have been made for validating the numerical prediction. A reasonably good agreement has been obtained between predicted and the experimental results. Also, it is seen that valve lift has a predominant effect on flow structure and it is found that with increase in valve lift there is a tendency for flow separation near the valve seat region. Page(s): 85-92

A simple method to evaluate the critical loads of cantilever columns with follower forces

Thu, 01 Apr 2004 00:00:00 GMT

Title: A simple method to evaluate the critical loads of cantilever columns with follower forces Authors: Raju, K Kanaka; Rao, G Venkateswara Abstract: A simple method, based on two term Galerkin method, is presented here to evaluate the critical loads of a uniform cantilever column with follower forces. Three types of follower forces are considered. If two terms are used in the Galerkin method, a quadratic equation for the frequency is obtained and the critical loads are evaluated by making the radical of the solution of the quadratic equation zero, avoiding a frequency mapping with the applied follower force. When the radical is zero, the value of the frequency obtained is the coalescence frequency. The accuracy of results obtained from the present method is quite suitable for engineering purposes. The accuracy can further be improved if suitable admissible functions, which represent the first two modes of vibration accurately, are chosen. Page(s): 143-146

Experimental investigation on the supersonic jet impingement

Thu, 01 Apr 2004 00:00:00 GMT

Title: Experimental investigation on the supersonic jet impingement Authors: Ghanegaonkar, P M; Ramanujachari, V; Vijaykant, S Abstract: In order to understand the effects of supersonic jet impingement, static tests are conducted in a small-scale rocket motor loaded with a typical nitramine propellant to produce a nozzle exit Mach number of 3. This jet is made to impinge on a plate aligned vertically to the nozzle axis. The distance between the nozzle exit and the plate is varied from 2 to 6 times the nozzle exit diameter. The pressure rise due to jet impingement on the plate has been measured using pressure transducers located at ten different radial locations. The pressure - time data are analyzed to get an insight into the flow field upstream of the plate. The maximum pressure exerted on the plate is about 20-30% of the maximum pressure generated in the combustion chamber. Ten static tests are carried out to obtain the effects of nozzle divergence angle, axial distance between the nozzle exit and the plate and the chamber stagnation pressure on the flow field. Page(s): 100-106