Abstract A theoretical model has been developed for core-annular flow of a very viscous oil core and a water annulus through a horizontal pipe. Special attention was paid to understanding how the buoyancy force on the core, resulting from any density difference between the oil and water, is counterbalanced. This problem was simplified by assuming the oil viscosity to be so high that any flow inside the core may be neglected and hence that there is no variation of the profile of the oil-water interface with time. In the model the core is assumed to be solid and the interface to be a solid/liquid interface. By means of the hydrodynamic lubrication theory it has been shown that the ripples on the interface moving with respect to the pipe wall can generate pressure variations in the annular layer. These result in a force acting perpendicularly on the core, which can counterbalance the buoyancy effect. To check the validity of the model, oil-water core-annular flow experiments have been carried out in a 5.08 cm and an 20.32-cm pipeline. Pressure drops measured have been compared with those calculated with the aid of the model. The agreement is satisfactory.

A theoretical model for core-annular flow of a very viscous oil core and a water annulus through a horizontal pipe

Optimal prediction of process parameters by GWO-KNN in stirring-squeeze casting of AA2219 reinforced metal matrix composites

CNC turning process parameters optimization on Aluminium 6082 alloy by using Taguchi and ANOVA

Investigation of film cooling on nose cone by a forward facing array of micro-jets in Hypersonic flow

Investigation of thermal conductivity and thermal resistance analysis on different combination of natural fiber composites of Banana, Pineapple and Jute

This paper discusses the performance enhancement of supersonic air intake model through the implementation of blunted leading edge to the cowl lip section of the model. A supersonic air intake model with sharp cowl leading edge is initially considered to numerically investigate its performance. Mach 3, supersonic intake flow through the base model has been simulated using commercial CFD package Ansys Fluent-15. Comparison of numerical predictions and experimental measurements is presented to demonstrate the correctness and accuracy of numerical frame work followed in the present study. Higher order spatial accuracy of the solver along with suitably refined mesh helped in accurate capturing of the flow field. Modification to the cowl lip is proposed as an effective method to improve the performance of the supersonic air intake. Two different blunted cowl leading edge geometries were investigated to identify the possible enhancement in performance parameters. Improvement in mass capture and combustion stability attained through the use of forward shifted blunt cowl leading edge is presented. It is also revealed through the present study that the blunt cowl leading edge can reduce the intensity of shock wave boundary layer interaction occurring at the isolator entry section. Deviation in total pressure recovery and flow distortion observed with different supersonic air intake models are also discussed with reasons for the same. This study demonstrates the scope of overall improvement in scramjet engine performance through the use of suitably positioned blunt cowl leading edge.

https://jafmonline.net/JournalArchive/download?file_ID=44250&issue_ID=246

Alterations of Cowl Lip for the Improvement of Supersonic-Intake Performance

Shock wave boundary layer interactions in hypersonic flows

Effect of leading edge bluntness on the interaction of ramp induced shock wave with laminar boundary layer at hypersonic speed

Numerical assessment of correlations for shock wave boundary layer interaction

Different compositions of graphene oxide (GO) and detonation nanodiamond (DND) nanoparticles with API CH-4 engine oil were tested on a reciprocating wear tester at high contact pressure. Significan...

Bibin John

Papers

Alterations of Cowl Lip for the Improvement of Supersonic-Intake Performance

Shock wave boundary layer interactions in hypersonic flows

Effect of leading edge bluntness on the interaction of ramp induced shock wave with laminar boundary layer at hypersonic speed

Numerical assessment of correlations for shock wave boundary layer interaction

Tribological performance of nanolubricants dispersed with graphene oxide and detonation nanodiamond