We describe behavior of the air-coal mixture using the Navier–Stokes equations for gas and particle phases, accompanied by a turbulence model. The undergoing chemical reactions are described by the Arrhenian kinetics (reaction rate proportional to exp ` − E RT ́ , where T is temperature). We also consider the heat transfer via conduction and radiation. Moreover we use improved turbulence-chemist...

Current expertise in air-water turbulent flows on stepped chutes is limited to laboratory experiments at low to moderate Reynolds numbers on flat horizontal steps. In this study, highly turbulent air-water flows skimming down a large-size stepped chute were systematically investigated with a 22o slope. Turbulence manipulation was conducted using vanes or longitudinal ribs to enhance interaction...

The present thesis aims to study the effect of human movements on local exhaust ventilation. In its simplest terms, local exhaust ventilation is a system which has the function of extracting contaminated air situated close to the contaminant source, protecting a working person from exposure to hazardous substances by containing or capturing them locally, at the emission point. As an important s...

A numerical study on Nox emission from an industrial furnace utilizing high temperature air combustion (HTAC) technology was done. The basic concept of the regenerative burner including heating a diluting of fresh air by flue gas was implemented in a two-dimensional furnace model. Governing equations in conjunction with a turbulence model and an overall chemistry model were solved using an impl...

In the present study, the conjugate turbulent free convection with the thermal surface radiation in a rectangular enclosure bounded by walls with different thermophysical characteristics in the presence of a local heater is numerically studied. The effects of surface emissivity and wall materials on the air flow and the heat transfer characteristics are the main focus of the present investigati...

We show quantitatively how the collision rate of droplets of visible moisture in turbulent air increases very abruptly as the intensity of the turbulence passes a threshold, due to the formation of fold caustics in their velocity field. The formation of caustics is an activated process, in which a measure of the intensity of the turbulence, termed the Stokes number St, is analogous to temperatu...

The dynamics of air ow during speech production may often result into some small or large degree of turbulence. In this paper, we quantify the geometry of speech turbulence as re ected in the fragmentation of the time signal by using fractal models. We describe an e cient algorithm for estimating the short-time fractal dimension of speech signals based on multiscale morphological ltering and di...

Fallstreak cirrus clouds are associated with supersaturated air, together with waves, instabilities and/or turbulence; however, their precise cause is usually uncertain. This paper uses already-published satellite, radiosonde and radar data, reanalysed to study some large fallstreaks which had been previously overlooked. The fallstreaks – up to 60 km long with a parent cloud 20 km wide – are ca...