The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Kenneth T Kiger - One of the best experts on this subject based on the ideXlab platform.
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Spray cooling using multiple Nozzles visualization and wall heat transfer measurements
Volume!, 2004Co-Authors: Bohumil Horacek, Kenneth T KigerAbstract:Time and space resolved heat transfer data on a nominally isothermal surface cooled by two Spray Nozzles was obtained using an array of individually controlled microheaters. Visualization and measurements of the liquid-solid contact area and three-phase contact line length were made using a total internal reflectance technique. The spacing between the Nozzles and the heated surface was varied between 7 mm and 17 mm. Little interaction between the two Sprays was observed for the tested conditions, with the heat flux produced by a single nozzle remaining comparable to that produced by two Nozzles, provided the areas considered were limited to the regions impacted by the Sprays. Variations in the heat transfer across the surface, however, increased significantly with decreasing spacing. The phase change heat transfer was strongly correlated with the length of the three-phase contact line.Copyright © 2004 by ASME
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Spray cooling using multiple Nozzles: visualization and wall heat transfer measurements
IEEE Transactions on Device and Materials Reliability, 2004Co-Authors: Bohumil Horacek, Kenneth T KigerAbstract:Time- and space-resolved heat transfer data on a nominally isothermal surface, cooled by two Spray Nozzles, were obtained using an array of individually controlled microheaters. Visualization and measurements of the liquid-solid contact area and three-phase contact line length were made using a total internal reflectance technique. The spacing between the Nozzles and the heated surface was varied between 7 and 17 mm. Little interaction between the two Sprays was observed for the tested conditions, with the heat flux due to a single nozzle remaining comparable to that due to two Nozzles, provided the areas considered were limited to the regions impacted by the Sprays. Variations in the heat transfer across the surface, however, increased significantly with decreasing nozzle-to-heater spacing. The phase change heat transfer was strongly correlated with the length of the three-phase contact line and was not correlated with the wetted area.
Bohumil Horacek - One of the best experts on this subject based on the ideXlab platform.
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Spray cooling using multiple Nozzles visualization and wall heat transfer measurements
Volume!, 2004Co-Authors: Bohumil Horacek, Kenneth T KigerAbstract:Time and space resolved heat transfer data on a nominally isothermal surface cooled by two Spray Nozzles was obtained using an array of individually controlled microheaters. Visualization and measurements of the liquid-solid contact area and three-phase contact line length were made using a total internal reflectance technique. The spacing between the Nozzles and the heated surface was varied between 7 mm and 17 mm. Little interaction between the two Sprays was observed for the tested conditions, with the heat flux produced by a single nozzle remaining comparable to that produced by two Nozzles, provided the areas considered were limited to the regions impacted by the Sprays. Variations in the heat transfer across the surface, however, increased significantly with decreasing spacing. The phase change heat transfer was strongly correlated with the length of the three-phase contact line.Copyright © 2004 by ASME
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Spray cooling using multiple Nozzles: visualization and wall heat transfer measurements
IEEE Transactions on Device and Materials Reliability, 2004Co-Authors: Bohumil Horacek, Kenneth T KigerAbstract:Time- and space-resolved heat transfer data on a nominally isothermal surface, cooled by two Spray Nozzles, were obtained using an array of individually controlled microheaters. Visualization and measurements of the liquid-solid contact area and three-phase contact line length were made using a total internal reflectance technique. The spacing between the Nozzles and the heated surface was varied between 7 and 17 mm. Little interaction between the two Sprays was observed for the tested conditions, with the heat flux due to a single nozzle remaining comparable to that due to two Nozzles, provided the areas considered were limited to the regions impacted by the Sprays. Variations in the heat transfer across the surface, however, increased significantly with decreasing nozzle-to-heater spacing. The phase change heat transfer was strongly correlated with the length of the three-phase contact line and was not correlated with the wetted area.
Lei Wang - One of the best experts on this subject based on the ideXlab platform.
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experimental characterization of heat transfer in non boiling Spray cooling with two Nozzles
Applied Thermal Engineering, 2011Co-Authors: Xiulan Huai, Lei WangAbstract:Heat transfer in a non-boiling Spray cooling system with de-ionized water as the working fluid is experimentally investigated. An open-loop test system with two full-cone Spray Nozzles used to generate water droplets to a heated surface is established for the cooling of high-power devices. The effects of the liquid volume flow rate, the nozzle-to-surface distance and the liquid inlet temperature on the heat transfer are scrutinized. It is found that the non-boiling Spray cooling system can remove high heat flux from a small surface while maintaining the surface at desirable low temperature. Increasing the liquid volume flow rate or reducing the liquid inlet temperature increases significantly the heat transfer coefficient. There exists an optimal nozzle-to-surface distance under which the heat transfer coefficient is maximized. It is also found that adding a surfactant to the working fluid with an appropriate concentration will further improve the heat transfer.
I. W. Kirk - One of the best experts on this subject based on the ideXlab platform.
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Droplet Spectra Classification for Fixed-Wing Aircraft Spray Nozzles
2001 Sacramento CA July 29-August 1 2001, 2020Co-Authors: I. W. KirkAbstract:Pesticide applicators should be knowledgeable about droplet spectra classification and compliance with crop protection product labels. Some pesticide product labels already specify application with a certain droplet spectra classification and labels for many new and reregistered products are expected to require application within a specified range of the Spray droplet spectrum (e.g., Medium or Coarse). Applicators of pesticides will need to know how to achieve the specified droplet spectra classification with their application. Spray nozzle parameters, pressure, and airspeed are primary factors that influence droplet spectra classification from aerial Spray Nozzles. Computer spreadsheet models for Spray Nozzles commonly used on fixed-wing aircraft were developed that will permit applicators to select their Spray nozzle, input operational conditions for an application, and predict the expected droplet spectra classification. Atomization models are presented for eight of the most commonly used Spray Nozzles on fixed-wing aircraft as determined from aerial applicator surveys. The models are available on diskette and web pages for applicator use. These models provide a tool that applicators can use to mitigate Spray drift and ensure compliance with crop protection product label requirements for applying Sprays with a specific droplet spectra classification.
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measurement and prediction of atomization parameters from fixed wing aircraft Spray Nozzles
Transactions of the ASABE, 2007Co-Authors: I. W. KirkAbstract:A survey of Spray Nozzles used by the agricultural aviation industry identified Nozzles and operating conditions that were most commonly used in applying agricultural chemicals in the U.S. Eleven hydraulic Nozzles and their typical range of operating conditions were selected from the survey. These eleven Nozzles were subjects of a research program to develop Spray atomization models that would be easy for aerial applicators to use in adjusting operations to control Spray drift from aerial agricultural Sprays. Each nozzle was conducted through a series of trials in a Spray nozzle test facility equipped with a laser spectrometer to develop a data set for atomization model development. Computer spreadsheet models were developed from the data set with operator selection of a specific Spray nozzle and inputs of nozzle orifice size, Spray discharge angle, Spray pressure, and aircraft airspeed. The model outputs included droplet size parameters, drift potential parameters, and droplet spectra classification. Aircraft speed was the dominating factor influencing atomization from most of the Spray nozzle models. Validation studies showed that the models gave useful estimates of the computed parameters for estimating compliance with product label and state regulatory agency requirements for Spray drift mediation. The models are available on-line and in a user handbook as well as in the current technical presentation.
Jose E. Navedo - One of the best experts on this subject based on the ideXlab platform.
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Optimal Spray characteristics in water Spray cooling
International Journal of Heat and Mass Transfer, 2004Co-Authors: Ruey-hung Chen, L.c. Chow, Jose E. NavedoAbstract:The dependence of the efficiency of liquid usage (η) at CHF on Spray parameters was experimentally investigated for subcooled water Spray cooling. A Spray can be characterized by three independent parameters (droplet Sauter-mean diameter, d32, droplet velocity, V, and droplet flux, N). In this study, each of these parameters was varied with the other two kept constant by using a combination of Spray Nozzles, operating pressures, and distance between the nozzle exit and the heater surface. It was found that CHF varies with N-2/3, d32-14/5and V14, respectively, when two of the three Spray parameters are kept nearly constant. It was also found that CHF varies with N1/6and V1/4and is relatively independent of d32. It is concluded that to achieve the maximum possible CHF while using the minimum quantity of water, it is desirable to select Nozzles that produce as small a droplet diameter with as high a velocity as possible. © 2004 Elsevier Ltd. All rights reserved.