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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Drag Reduction with the Aid of Air Bubbles and Additives

Baghaei, Pouria January 2009 (has links)
The effect of additives on friction loss in upward turbulent flow was investigated in this experimental study. Additives such as air bubbles, frother and polymer were added to water flow to study their influence on the friction factor. In order to perform this research an experimental set-up was designed and developed. The test sections of the set-up consisted of three vertical pipes of different diameters. The set-up was equipped with three pressure transducers, a magnetic flowmeter, gas spargers and a gas rotameter. The first phase of the experimental program involved calibration of the various devices and pipelines test-sections. The single-phase pressure loss data obtained from the pipelines exhibited good agreement with the standard equations. The second phase of the experimental program dealt with the effect of air bubbles and additives (frother and polymer) on drag reduction in turbulent flows. The experimental results showed that bubbles in the range of 1 mm-3 mm increased the wall shear stress. Therefore, no drag-reduction effect was observed. On the contrary, a significant increase in friction factor was observed at low Reynolds numbers as a result of larger bubble sizes and lower turbulence intensities. The friction factor at low Reynolds numbers could be decreased by decreasing the bubble size by addition of frother to the flow system. The combination of polymer and air bubbles showed a drag reduction of up to 60%. It is also evident from the experiment results that the addition of polymer to bubbly flow system leads to fully homogeneous mixture.
2

Drag Reduction with the Aid of Air Bubbles and Additives

Baghaei, Pouria January 2009 (has links)
The effect of additives on friction loss in upward turbulent flow was investigated in this experimental study. Additives such as air bubbles, frother and polymer were added to water flow to study their influence on the friction factor. In order to perform this research an experimental set-up was designed and developed. The test sections of the set-up consisted of three vertical pipes of different diameters. The set-up was equipped with three pressure transducers, a magnetic flowmeter, gas spargers and a gas rotameter. The first phase of the experimental program involved calibration of the various devices and pipelines test-sections. The single-phase pressure loss data obtained from the pipelines exhibited good agreement with the standard equations. The second phase of the experimental program dealt with the effect of air bubbles and additives (frother and polymer) on drag reduction in turbulent flows. The experimental results showed that bubbles in the range of 1 mm-3 mm increased the wall shear stress. Therefore, no drag-reduction effect was observed. On the contrary, a significant increase in friction factor was observed at low Reynolds numbers as a result of larger bubble sizes and lower turbulence intensities. The friction factor at low Reynolds numbers could be decreased by decreasing the bubble size by addition of frother to the flow system. The combination of polymer and air bubbles showed a drag reduction of up to 60%. It is also evident from the experiment results that the addition of polymer to bubbly flow system leads to fully homogeneous mixture.
3

Innovative Milk Foamer : Product Development

Axelsson, Stefan January 2010 (has links)
<p>This report presents the primary development process of an innovative milk foamer. The project is structured as the primary development process that is used at Electrolux Floor Care and Small Appliances AB, Global Primary Development and Innovation department in Stockholm, Sweden. The aim was to develop a milk foamer with innovative solutions to provide Electrolux with a unique product. The objective was to create a product that highly meets customer requirements and in the same time is feasible to develop into a selling product. All the aspects regarding a consumer product had to be considered. To create innovative solutions thorough investigations of the physics behind foaming and foam are studied and documented. The difference in foam quality when using different ways of foaming is documented and possible explanations is discussed. The primary development process range from pre-study and customer research to designing prototypes and verifications. Most of the report deals with standalone solutions but there is also a part of the report that deals with integrated solutions and cooperating solutions that would be used together with espresso machines. The result is a variety of concepts and four fully working standalone prototypes. Two prototypes are further developed and are highly interesting to Electrolux.</p>
4

Innovative Milk Foamer : Product Development

Axelsson, Stefan January 2010 (has links)
This report presents the primary development process of an innovative milk foamer. The project is structured as the primary development process that is used at Electrolux Floor Care and Small Appliances AB, Global Primary Development and Innovation department in Stockholm, Sweden. The aim was to develop a milk foamer with innovative solutions to provide Electrolux with a unique product. The objective was to create a product that highly meets customer requirements and in the same time is feasible to develop into a selling product. All the aspects regarding a consumer product had to be considered. To create innovative solutions thorough investigations of the physics behind foaming and foam are studied and documented. The difference in foam quality when using different ways of foaming is documented and possible explanations is discussed. The primary development process range from pre-study and customer research to designing prototypes and verifications. Most of the report deals with standalone solutions but there is also a part of the report that deals with integrated solutions and cooperating solutions that would be used together with espresso machines. The result is a variety of concepts and four fully working standalone prototypes. Two prototypes are further developed and are highly interesting to Electrolux.

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