City Research Online

Abstract

The non-invasive liquid-crystal and schlieren methods have been applied to the study of convective heat transfer in rib-roughened channels.

The importance of investigating heat transfer from rib-roughened surfaces and of using non-invasive tools to gain information on thermal fields for similar complex geometries is stressed in Chapter 1.

Chapter 2 is devoted to a description of main important published papers related to this project. Firstly, studies concerning heat transfer from rib-roughened surfaces in forced and free convection are listed and discussed in detail. Moreover, a literature survey on optical methods in heat transfer is presented, with special attention to the methods (liquid-crystal thermography and schlieren) applied in this study.

Experiments performed by using liquid-crystal thermography are presented and discussed in Chapter 3. Three configuration geometries have been investigated: a smooth channel (having flat plates) and two different ribbed channels. The investigated heat transfer mechanism was forced convection. These experiments were performed at City University, London.

Chapter 4 is devoted to experiments performed by using the schlieren optical technique. Again, the experimental study included a preliminary activity on smooth channels, followed by tests performed for rib-roughened channels. The heat transfer mechanism was natural convection. These experiments, which constitute the main body of the project, were conducted at the Dipartimento di Termoenergetica e Condizionamento Ambientale, Universita di Genova, Italy.

Finally, most important conclusions are drawn in Chapter 5. Details of relationships between the recorded optical data and the thermal field (or heat transfer coefficients) are reported in Appendix Al and A2 for the liquid-crystal thermography and the schlieren method, respectively.

Publication Type:	Thesis (Doctoral)
Subjects:	T Technology > TJ Mechanical engineering and machinery
Departments:	Doctoral Theses School of Science & Technology > Engineering

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