A design process for propellers for the agitation of high viscous fluids based on the design analysis of wind turbine blades

  • The subject of this thesis is the design of axial flow machines. The type of turbomachine under examination is used to supply energy for high viscous fluid flow, as used in mixing and stirring tasks. The high viscous media treated in these tasks usually have non-Newtonian fluid properties. This kind of fluid flow is frequently associated with the field of energy and process engineering. In order to narrow down the problem described, the field of turbomachinery is restricted to the consideration of propellers. Propellers are used in a wide range of fluid mechanics tasks. In the form of wind turbines, propellers extract kinetic energy from a control room and thereby slow down the flow. Propeller stirrers, on the other hand, increase the energy level of a flow and accelerate it. Both machines are based on the same principle - only the direction of the energy flow is to be considered as the opposite direction. The design of new agitators is usually based on experience. Often, agitators are, therefore, not flow-optimised, and cannot be optimally operated. In this thesis, it is investigated whether the design processes of modern wind turbines, which are considered to be mature, can be adapted in order to generate a flow-optimised geometry for this type of turbomachine as well. This thesis will first examine the basics of wind turbine design processes. Special attention will be paid to the differences caused by the viscous fluid properties under consideration. The highly viscous behaviour of the fluids under consideration means that the theoretical fundamentals have to be extended as a result. Such extensions are identified and supplement the theoretical basis. The thesis will then present and examine an analytically based design process for flow-optimised propeller mixers. The procedure is based on blade element momentum theory. Application of blade element momentum theory requires detailed knowledge of the aerodynamic behaviour of the profiles used. This behaviour is usually only known for low viscosity and high-Re applications, as is usually the case for wind turbines or propeller engines. Comprehensive profile characteristics are not available for highly viscous and low-Re applications. In this thesis, these basics are generated using numerical methods. In the next step, the newly introduced design method is combined with the results of the investigations of profile aerodynamics for high viscous low-Re fluid flow. This combination is done using a calculation process which produces the flow-optimised geometry of a propeller mixer. The theoretical principles of the methods are implemented in an algorithm in such a way that the resultant turbomachine can be designed for a previously selected operating point, the design point. In contrast to classical turbomachinery, the design point additionally requires the specification of viscous fluid properties. However, in practical use, the final selected operating point of a turbomachine is often not the design point. The algorithm is examined for its suitability for inverse power calculation as well in order to compute the complete characteristic curve for a previously generated propeller mixer already in the design process.

Download full text files

Export metadata

Metadaten
Author:Thomas ReviolORCiD
URN:urn:nbn:de:hbz:386-kluedo-65097
Publisher:Shaker Verlag
Place of publication:Düren
Advisor:Martin Böhle
Document Type:Habilitation
Language of publication:English
Date of Publication (online):2021/09/30
Year of first Publication:2021
Publishing Institution:Technische Universität Kaiserslautern
Granting Institution:Technische Universität Kaiserslautern
Acceptance Date of the Thesis:2021/06/29
Date of the Publication (Server):2021/08/09
Tag:Design process; High viscous fluids; Mixing; Propeller
Page Number:XVII, 304
Source:Shaker Verlag, ISBN 978-3-8440-8188-6
Faculties / Organisational entities:Kaiserslautern - Fachbereich Maschinenbau und Verfahrenstechnik
DDC-Cassification:6 Technik, Medizin, angewandte Wissenschaften / 620 Ingenieurwissenschaften und Maschinenbau
Licence (German):Zweitveröffentlichung