Modeling Dynamic Response of an Actuator for Individual Nozzle Control of Agricultural Spray Flow Rate and Droplet Size

2012 ◽  
Vol 55 (2) ◽  
pp. 371-377
Author(s):  
D. L. Needham ◽  
A. J. Holtz ◽  
D. K. Giles
Keyword(s):  
Dynamic Response ◽  
Droplet Size ◽  
Flow Rate ◽  
Spray Flow Rate

scholarly journals Model based decision support system of operating settings for MMAT nozzles

2016 ◽  
Vol 56 (2) ◽  
pp. 178-185 ◽  
Author(s):  
Bradley Keith Fritz ◽  
Zbigniew Czaczyk ◽  
Wesley Clint Hoffmann
Keyword(s):  
Decision Support ◽  
Experimental Design ◽  
Decision Support System ◽  
Droplet Size ◽  
Flow Rate ◽  
Support System ◽  
Computational Models ◽  
Ease Of Use ◽  
Size Spectrum ◽  
Orifice Size

Abstract Droplet size, which is affected by nozzle type, nozzle setups and operation, and spray solution, is one of the most critical factors influencing spray performance, environment pollution, food safety, and must be considered as part of any application scenario. Characterizing spray nozzles can be a timely and expensive proposition if the entire operational space (all combinations of spray pressure and orifice size, what influence flow rate) is to be evaluated. This research proposes a structured, experimental design that allows for the development of computational models for droplet size based on any combination of a nozzle’s potential operational settings. The developed droplet size determination model can be used as Decision Support System (DSS) for precise selection of sprayer working parameters to adapt to local field scenarios. Five nozzle types (designs) were evaluated across their complete range of orifice size (flow rate*) and spray pressures using a response surface experimental design. Several of the models showed high level fits of the modeled to the measured data while several did not as a result of the lack of significant effect from either orifice size (flow rate*) or spray pressure. The computational models were integrated into a spreadsheet based user interface for ease of use. The proposed experimental design provides for efficient nozzle evaluations and development of computational models that allow for the determination of droplet size spectrum and spraying classification for any combination of a given nozzle’s operating settings. The proposed DSS will allow for the ready assessment and modification of a sprayers performance based on the operational settings, to ensure the application is made following recommendations in plant protection products (PPP) labels.

Study on Boiling Heat Transfer and Critical Heat Flux in Mist Cooling: Effect of Droplet Size on Heat Transfer Characteristics

2004 ◽  
Author(s):  
Hiroyasu Ohtake ◽  
Tomoyasu Tanaki ◽  
Yasuo Koizumi
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Critical Heat Flux ◽  
Droplet Size ◽  
Flow Rate ◽  
Mass Flux ◽  
Boiling Heat Transfer ◽  
Heat Transfer Characteristics ◽  
Liquid Mass ◽  
Mist Cooling

Boiling heat transfer and critical heat flux—CHF—in mist cooling were investigated experimentally and analytically. Especially, the heat transfer in the mist cooling was examined focusing on the effects of droplet size and droplet velocity on the heat transfer characteristics. Steady state experiments of heat transfer were conducted using a pure copper cylinder and mist flow of water-air at room temperature. Liquid flow rate was 0.3, 0.9, 1.8, 4 and 8 l/hr, respectively; each air flow rate on normal condition was 0, 40, 75 and 120 lN/min. Furthermore, liquid mass flux on the heater surface for each experimental condition was measured by using a cylinder with a scale and the same diameter as the heater. Distribution of air velocity, average velocity of droplets and average diameter of droplets were measured by using a fine Pitot tube, laser doppler anemometry and immersion method, respectively. Three correlations of the mist cooling rate for non-boiling, evaporation of droplets and evaporation of the liquid film were developed by using the measured liquid mass flux, characteristic droplet velocity and wall superheat. A CHF model was presented by focusing on maximum evaporation rate of the liquid mass flux on a heater. A droplet evaporation model was proposed by using the transient heat conduction in a sphere. Finally, three dimensionless correlations for the mist cooling were presented.

Experimental Investigation of the Effects of a Pulsating Internal Flow on the Dynamics of a Submersed U-Shaped Flexible Pipe

2012 ◽  
Author(s):  
Marcio Yamamoto ◽  
Shotaro Uto ◽  
Tomo Fujiwara ◽  
Motohiko Murai
Keyword(s):  
Dynamic Response ◽  
Flow Rate ◽  
Deep Sea ◽  
New Technologies ◽  
Fluid Pressure ◽  
Internal Flow ◽  
Flexible Pipe ◽  
Hydrocarbon Production ◽  
Petroleum Production ◽  
Single Well

In the past of the offshore petroleum production, each riser had conveyed the hydrocarbon production from a single vertical well; the riser’s internal flow rate was relatively low and only the internal fluid pressure was taking into account for the riser analysis. Other internal flow effects, such as internal fluid’s linear moment, and Coriollis effects, were neglected. However, the paradigm for petroleum production in ultra-deepwater is shifting nowadays. New technologies, such as horizontal wells, have increased the production rate from a single well. In addition, a subsea booster system can increase both pressure and flow rate of the riser’s conveyed fluid. Further, the Offshore Mining is rising as a new industry and will demand riser systems to convey, at high flow rates, the mineral ore’s slurry from the seafloor up to the production support vessel. In a previous experiment, the effects of the internal flow on a vertical riser were investigated. In the current experiment, the main objective is to investigate the effect of the internal flow on the dynamic response of a pipe in “jumper configuration”. The experiment was carried out at the Deep Sea Basin of the National Maritime Research Institute using a 10 m long flexible pipe. The actual “jumper” is a piece of flexible riser, in U-shaped configuration, that connects the main structure of “Self-Standing Hybrid Riser” to the production vessel. During the experiment, fresh water was pumped into the model by positive displacement pump; and an oscillator applies a harmonic vibration on one pipe’s end. Then the pipe’s dynamic response is measured by the Deep Sea Basin’s 3D Visual Measurement System. Results for different internal flows and oscillations are compared.

Preparing Monodispersed Hydrogel Microspheres and Microcapsules

1998 ◽  
Vol 550 ◽  
Author(s):  
Y. Senuma ◽  
Ch. Lowe ◽  
Y. Zweifel ◽  
J. G. Hilborn ◽  
I. Marison
Keyword(s):  
Size Distribution ◽  
Droplet Size ◽  
Flow Rate ◽  
Large Scale ◽  
Alginate Beads ◽  
Model System ◽  
Drop Formation ◽  
Narrow Size Distribution ◽  
Spinning Disk ◽  
High Degree

AbstractOur spinning disk atomization (SDA) can, relative to other existing techniques, produce micronsized particles of very narrow size distribution. The aim of this work is to present this technology for the production of alginate microspheres. We have atomized and gelled aqueous alginate solutions into very narrowly dispersed microspheres with sizes ranging from 300 to 600 μm. Here the interest is to design particles of a given size with a narrow size distribution and to show a new method of encapsulation using the SDA. The viscosity and flow rate contributions in the drop formation is qualitatively analyzed to show how it affects the droplet size. In addition, a technique for high degree of encapsulation will be presented. As an example, yeast has been used as a model system. The production of yeast loaded microspheres will show the potential of the technique for biotechnology applications. Such alginate beads could potentially serve as carriers for acitive substances or cells in large scale bioreactors.

scholarly journals Heat transfer in a novel microwave heating device coupled with atomization feeding

2021 ◽  
pp. 288-288
Author(s):  
Shangzhi Yu ◽  
Qinglong Xie ◽  
Xiaoning Mao ◽  
Ying Duan ◽  
Yong Nie
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
High Temperature ◽  
Microwave Heating ◽  
Flow Rate ◽  
Orifice Diameter ◽  
Spray Parameters ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Spray Flow Rate

The heat transfer characteristics of the microwave heating coupled with atomization feeding were investigated using ethanol as the spray medium on a pressure swirl nozzle. The effects of spray height, flow rate and temperature on the sauter mean diameter (SMD) of atomized droplets were examined. The results showed that the droplet SMD was 12-130 ?m, which increased with the spray height and decreased with the flow rate and temperature of spray medium. Through the fitting of the experimental data, the dimensionless correlation of the droplet SMD which was based on orifice diameter, Reynolds and Ohnesorge numbers was obtained. The calculated results were basically consistent with the experimental data within 15% error. The heat transfer characteristics of atomized droplets on high-temperature surface of SiC bed heated by microwave were then investigated. The effects of spray flow rate, spray height and spray temperature on the heat transfer characteristics were examined. The power of spray heat transfer decreased with the temperature and increased with the spray flow rate and spray height. The dimensionless correlation to describe the heat transfer characteristics of atomized droplets on the high-temperature SiC surface under the microwave heating was obtained which included thermophysical properties of spray medium, spray parameters, and temperatures of the high-temperature bed surface and spray medium, with the error of ?20%. These correlations can be used to predict the SMD of the atomized droplets and the power of spray heat transfer in the microwave heating process.

Sign in / Sign up

Export Citation Format

Share Document