A 1arge-scale tumble rather than swirl would exist in cylinders in the case of two valves’ opening in a fourvalve engine. A strong swirl is generated when one valve is closed, yet the flow capacity is less than that of two valves being opened. In order to change it, different lifts of valves (DLV) present are achieved. In the case of using different lifts of two intake valves, both tumble and s...

A newly developed heavy duty diesel engine in dual fuel mode of operation has been studied in detail. The main fuel would be natural gas and diesel oil as pilot injection. The importance and effects of mixture preparation and formation through ports, valves and in cylinder flow field with different swirl ratio and tumble on diesel combustion phenomena is an accepted feature which has been studi...

The effect of inlet swirl on the flow development and combustion dynamics in a lean-premixed swirl-stabilized combustor has been numerically investigated using a large-eddy-simulation (LES) technique along with a level-set flamelet library approach. Results indicate that when the inlet swirl number exceeds a critical value, a vortex-breakdown-induced central toroidal recirculation zone is estab...

The influence of swirl on the shape of the Burke-Schumann reaction sheet in a straight cylindrical pipe is investigated by asymptotic and numerical means. Attention is confined to swirl levels that are near the critical value at which vortex breakdown occurs. A high Reynolds number, laminar, isothermal, low Mach number reacting flow is considered. An asymptotic analysis is developed to study th...

Flame stabilization by swirl is a common feature of many combustors. While most of the swirl combustors are enclosed, there have been relatively few studies of open swirl-stabilized flames. In the current study, an open swirl-stabilized turbulent premixed flame is studied numerically. The purpose of this work is to obtain a better understanding of the flame properties by simulating the flow fie...

One-dimensional stability analysis of a hydraulic system composed of a penstock, a runner, and a draft tube was carried out to determine the cause of the full load draft tube surge. It is assumed that the cavity volume at the runner exit is a function of the pressure at the vortex core evaluated from the instantaneous local pressure at the runner exit and an additional pressure decrease due to ...

The paper presents large eddy simulation of unconfined swirling jets. In the first part, an unconfined annular jet is investigated for swirl numbers ranging from 0 to 1.2. The impact of the swirl on the mean flow and the precessing vortex structures in this flow is analysed. In the second part of the paper, a co-annular pilot jet is introduced near the axis. The investigations show that the add...

The central recirculation zone (CRZ) in a swirl stabilized gas turbine combustor has a dominant effect on the fuel air mixing process and flame stability. Most of state of the art swirlers share one disadvantage; the fixed swirl number for the same swirler configuration. Thus, in a mathematical sense, Reynolds number becomes the sole parameter for controlling the flow characteristics inside the...

The objective of this work is to investigate the turbulent reacting flow in a three dimensional combustor with emphasis on the effect of inlet swirl flow through a numerical simulation. Flow field is analyzed using the SIMPLE method which is known as stable as well as accurate in the combustion modeling, and the finite volume method is adopted in solving the radiative transfer equation. In this...

Bubbles in coating color greatly influence the paper quality and coater runnability. It is particularly important technology to remove bubbles for the paper coating industry. Recently, one of the authors has developed a novel device using swirl flow capable of eliminating bubbles and decreasing dissolved gases from fluid. This device is called the “Bubble Eliminator”. Using the bubble eliminato...