Investigation of large-scale cooling system fan vibration
| dc.contributor.advisor | Els, Danie J. | en_ZA |
| dc.contributor.advisor | Van der Spuy, S. J. | en_ZA |
| dc.contributor.author | Muiyser, Jacques | en_ZA |
| dc.contributor.other | Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering. | en_ZA |
| dc.date.accessioned | 2016-12-22T13:38:50Z | |
| dc.date.available | 2016-12-22T13:38:50Z | |
| dc.date.issued | 2016-12 | |
| dc.description | Thesis (DEng)--Stellenbosch University, 2016. | en_ZA |
| dc.description.abstract | ENGLISH ABSTRACT: Air-cooled condenser fans operate under distorted inlet air flow conditions that may lead to high levels of blade vibration. Three case studies were considered where full-scale strain gauge measurements were conducted at three separate fan installations. The measurements showed high dynamic blade loading for two of these cases. Laboratory experiments confirmed that blade vibration is a function of inlet flow distortion as well as downstream flow obstructions such as the fan bridge. These findings were used to create a potential flow simulation that can be used to determine the aerodynamic blade loading profile exerted on a fan blade as a function of its rotational position. The simulated load profile for a fan operating under distorted inlet air flow conditions was applied to a dynamically equivalent finite element representation of the fan blade. Good correlation between the simulated and measured response of the fan blade was found. Using this same load profile as excitation force in the multibody simulation of the dynamics of a complete fan system, it was found that the effect of supporting bridge stiffness is negligible when compared to the effect of the ratio between the fan’s rotational speed and the first natural frequency of the blades. This same result was obtained when modelling the fan system as a collection of single degree-offreedom subsystems and applying an equivalent aerodynamic load obtained from a measured response. The results obtained in this study were tested against the test cases where the different observations could be explained. Additionally, design recommendations could be generated based on the fan system’s structural and operational parameters. | en_ZA |
| dc.description.abstract | AFRIKAANSE OPSOMMING: Lugverkoelde kondensator-waaiers funksioneer onder verwronge inlaat-vloei omstandighede wat kan lei tot hoë vlakke van lem-vibrasie. Drie gevallestudies waar volskaalse vervormings-metings uitgevoer is op drie aparte waaier-installasies, is oorweeg. Die metings het hoë dinamiese lem-belasting getoon vir twee van die gevalle. Laboratorium eksperimente het bevestig dat lem-vibrasie ’n funksie is van verwronge inlaat-vloei omstandighede sowel as obstruksies verder in die stelsel, soos bv. die waaier-brug. Hierdie bevindings is gebruik om ’n potensiaalvloei-simulasie te skep wat gebruik kan word om die aërodinamiese lem-belastingsprofiel wat uitgeoefen word op ’n waaierlem as ’n funksie van die omwentelingsposisie te bepaal. Die gesimuleerde belastingsprofiel vir ’n waaier wat onder verwronge inlaat-vloei omstandighede werk is aangewend op ’n dinamiese ekwivalente eindige element voorstelling van die waaierlem. Daar is goeie korrelasie gevind tussen die gesimuleerde en gemete reaksie van die waaierlem. Deur gebruik te maak van dieselfde belastingsprofiel as opwekkingskrag in die multi-liggaam simulasie van die volledige waaierstelsel, is daar gevind dat die effek van die ondersteunende brug-styfheid onbeduidend is wanneer dit vergelyk word met die effek van die verhouding tussen die waaier se rotasie-spoed en die eerste natuurlike frekwensie van die lemme. Dieselfde resultaat is verkry toe die waaier-stelsel gemodelleer is as ’n versameling van enkel vryheidsgraad substelsels, en ’n ekwivalente aërodinamiese belasting verkry vanaf ’n gemete reaksie aangewend is. Die resultate behaal in hierdie studie is getoets teen toetsgevalle waar die verskillende waarnemings verduidelik kan word. Bykomend kan daar ontwerpsvoorstelle ontwikkel word gebaseer op die waaierstelsel se strukturele en operasionele parameters. | af_ZA |
| dc.format.extent | xviii, 148 pages : illustrations | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/10019.1/100309 | |
| dc.language.iso | en_ZA | en_ZA |
| dc.publisher | Stellenbosch : Stellenbosch University | en_ZA |
| dc.rights.holder | Stellenbosch University | en_ZA |
| dc.subject | Air conditioning -- Equipment and supplies | en_ZA |
| dc.subject | Cooling systems | en_ZA |
| dc.subject | Axial flow | en_ZA |
| dc.subject | Aerodynamics -- Mathematical models | en_ZA |
| dc.subject | UCTD | en_ZA |
| dc.title | Investigation of large-scale cooling system fan vibration | en_ZA |
| dc.type | Thesis | en_ZA |