Study on the atomization zones of the nozzle in the processes of material primary processing

It can divide the atomization effect in the direction of the nozzle axial injection into the jet area and the non-jet area by using the second crushing theory. On this basis, according to the feed liquid atomization particles discrete degree index of characteristics particle size of feed liquid atomization, it divides the injection zone into the atomization area and the diffusion area, so as to realize the axial direction of jet nozzle injection zone, atomization zone and the diffusion zone accurately. Simulation and experiment are used to verify the three zones of atomization nozzle. The division of three zones drives the study from the whole space of liquid distribution in the roller to atomization zone, clears the key zone of the roller in tobacco primary processing, and provides a basis for further work.

Electrostatic Induction Spray-charging System (Embedded Electrode) for Knapsack Mist-blower

The introduction of electrically charged sprays in agricultural application has become inevitable for better control on droplet transference with reduced drift with less spray chemical requirements. The study was under taken to develop an electrostatic induction spray charging system as attachment to knapsack mist-blower. A high voltage generator was fabricated on the basis of Cockcroft-Walton voltage multiplier principle with input of 6 V DC battery. A self-atomizing hydraulic nozzle was developed to deliver the droplet spectrum required for effective electrostatic charge induction. The prototype was evaluated for charge to mass ratio (mC. kg-1) at five electrode potentials (1 kV, 2 kV, 3 kV, 4 kV and 5 kV) at four electrode placement positions from atomization zone (0, 5, 10 and 15 mm). The charge mass ratio (CMR) value of spray cloud was measured using Faradays Cage at five positions from nozle tip (50, 100, 150, 200 and 250 cm). The electrode voltage potential at 5 kV at its position 5 mm from the atomization zone shown the maximum CMR value of 1.088 mC.kg-1. In contrast with commercial system (ESS-MBP90) it was observed that except at 50 cm distance, the developed charging system, at 4 kV and 5 kV, surpassed commercial system in CMR from 100 cm to 250 cm distances. The droplet spectrum of the developed system was analysed and observed that the size of droplets were 100 to 200 µm. The developed system found to be cost effective and significantly consistent over the commercial one.

Simulation of Liquid Fuel Atomization in an Industrial Spray Nozzle of a Powerplant Boiler

In this study, the liquid fuel atomization in the injector nozzle of the combustion chamber of a powerplant boiler is numerically simulated. The atomization of a liquid fuel injector is characterized by drop size distribution of the nozzle. This phenomenon plays an important role in the performance of the combustion chamber such as the combustion efficiency, and the amount of soot and NOx formation inside the boiler. The injector nozzle, considered in this study, belongs to a powerplant boiler where the liquid fuel is atomized using a high pressure steam. First, the geometric characteristics of the injector are carefully analyzed using a wire-cut process and a CAD model of the nozzle is created. Next, one of the nozzle orifices and the atomization zone where the high pressure steam meets the liquid fuel is recognized. The computational domain is extended long enough to cover the whole atomization zone up to the end of the orifice. The flow governing equations are the continuity and Navier-Stokes equations. For tracking the liquid/gas interface, the Volume-of-Fluid (VOF) method along with Youngs’ algorithm for geometric reconstruction of the free surface is used. The simulation results show the details of the liquid and steam flow inside the nozzle including velocity distribution and shape of the liquid/gas interface. It is found that the liquid breakup to ligaments and the atomization of liquid to droplets do not occur inside the nozzle orifice. A liquid jet with certain cross sectional shape leaves the orifice surrounded by a high speed steam. The numerical model provides the shape of the liquid jet, and the steam and fuel velocity distributions at the exit of the nozzle orifice. These parameters are then correlated to the final drop size distribution using analytical/experimental correlations available in literature.