Experimental investigation of the effect of superhydrophobic coating and microbubble lubrication on the resistance of a scaled ship model

Lee, Paul

dc.contributor.author	Lee, Paul	en
dc.date.accessioned	2020-05-26T13:46:56Z
dc.date.available	2020-05-26T13:46:56Z
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/50658
dc.identifier.uri	http://dx.doi.org/10.26240/heal.ntua.18356
dc.rights	Default License
dc.subject	Drag reduction	en
dc.subject	Microbubble lubrication	en
dc.subject	Superhydrophobic coating	en
dc.subject	Ship resistance	en
dc.title	Experimental investigation of the effect of superhydrophobic coating and microbubble lubrication on the resistance of a scaled ship model	en
heal.type	bachelorThesis
heal.classification	Hydrodynamics	en
heal.classification	Marine Engineering	en
heal.language	en
heal.access	free
heal.recordProvider	ntua	el
heal.publicationDate	2019-09-16
heal.abstract	Skin friction of a fluid flowing near a solid surface poses many problems in variety applications. Increased energy consumption in marine and aerospace vehicles and decreased performances in hydraulic systems are one of the major issues to name a few. Thus, reduction of frictional drag leads to obvious technological advantages from an engineering perspective with additional economical and environmental benefits. Various studies and intense research have been conducted by the scientific community in order to propose effective ways to reduce frictional drag. Few of the many techniques are the reduction of resistance through super water repellent coatings, also known as superhydrophobic, and microbubble injection in the boundary layer. In this thesis, the effectiveness of the aforementioned techniques is tested experimentally by comparing the total resistance of a ship model with and without the introduction of microbubbles under the condition of a superhydrophobic coated surface in order to examine the performance difference between them. The flat of bottom of a 2.52 [m] long ship model is treated with a special nano-ceramic coating and a microbubble generator attached on the stem is able to produce fine bubbles of 50 [μm] diameter. The total resistance is recorded at towing speeds of 1.5, 2.0, and 2.5 [m/s], at an even keel and 0.5o trim by stern condition, and a maximum of 4.5% reduction of the frictional coefficient is noted. This paper is divided into four chapters. The 1st chapter provides an introduction to the skin friction problem in maritime, a literature review, and a proposal of an experimental concept. Chapter 2 provides details of the microbubble generator and its setup while chapter 3 presents the implementation of the experimental concept and necessary optimizations. Analysis of the measurements data are presented in the last chapter with final notes.	en
heal.advisorName	Triantafyllou, George	en
heal.committeeMemberName	Triantafyllou, George	en
heal.committeeMemberName	Gregory, Grigoropoulos	en
heal.committeeMemberName	Papadakis, George	en
heal.academicPublisher	Εθνικό Μετσόβιο Πολυτεχνείο. Σχολή Ναυπηγών Μηχανολόγων Μηχανικών. Τομέας Ναυτικής και Θαλάσσιας Υδροδυναμικής. Εργαστήριο Ναυτικής και Θαλάσσιας Υδροδυναμικής	el
heal.academicPublisherID	ntua
heal.numberOfPages	56 σ.
heal.fullTextAvailability	false