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A CFD STUDY OF CAVITATION IN REAL SIZE DIESEL INJECTORS

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A CFD STUDY OF CAVITATION IN REAL SIZE DIESEL INJECTORS

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dc.contributor.advisor Margot, Xandra Marcelle es_ES
dc.contributor.author Patouna, Stavroula es_ES
dc.date.accessioned 2012-02-17T07:43:48Z
dc.date.available 2012-02-17T07:43:48Z
dc.date.created 2012-02-10T09:00:00Z es_ES
dc.date.issued 2012-02-17T07:43:43Z es_ES
dc.identifier.uri http://hdl.handle.net/10251/14723
dc.description.abstract In Diesel engines, the internal flow characteristics in the fuel injection nozzles, such as the turbulence level and distribution, the cavitation pattern and the velocity profile affect significantly the air-fuel mixture in the spray and subsequently the combustion process. Since the possibility to observe experimentally and measure the flow inside real size Diesel injectors is very limited, Computational Fluid Dynamics (CFD) calculations are generally used to obtain the relevant information. The work presented within this thesis is focused on the study of cavitation in real size automotive injectors by using a commercial CFD code. It is divided in three major phases, each corresponding to a different complementary objective. The first objective of the current work is to assess the ability of the cavitation model included in the CFD code to predict cavitating flow conditions. For this, the model is validated for an injector-like study case defined in the literature, and for which experimental data is available in different operating conditions, before and after the start of cavitation. Preliminary studies are performed to analyze the effects on the solution obtained of various numerical parameters of the cavitation model itself and of the solver, and to determine the adequate setup of the model. It may be concluded that overall the cavitation model is able to predict the onset and development of cavitation accurately. Indeed, there is satisfactory agreement between the experimental data of injection rate and choked flow conditions and the corresponding numerical solution.This study serves as the basis for the physical and numerical understanding of the problem. Next, using the model configuration obtained from the previous study, unsteady flow calculations are performed for real-size single and multi-hole sac type Diesel injectors, each one with two types of nozzles, tapered and cylindrical. The objective is to validate the model with real automotive cases and to ununderstand in what way some physical factors, such as geometry, operating conditions and needle position affect the inception of cavitation and its development in the nozzle holes. These calculations are made at full needle lift and for various values of injection pressure and back-pressure. The results obtained for injection rate, momentum flux and effective injection velocity at the exit of the nozzles are compared with available CMT-Motores Térmicos in-house experimental data. Also, the cavitation pattern inside the nozzle and its effect on the internal nozzle flow is analyzed. The model predicts with reasonable accuracy the effects of geometry and operating conditions. es_ES
dc.language Inglés es_ES
dc.rights Reserva de todos los derechos es_ES
dc.source Riunet es_ES
dc.subject Cavitation es_ES
dc.subject Diesel injector es_ES
dc.subject Finite volume method es_ES
dc.subject Cfd es_ES
dc.subject Nozzle flow es_ES
dc.subject.classification INGENIERIA AEROESPACIAL es_ES
dc.subject.classification MAQUINAS Y MOTORES TERMICOS es_ES
dc.title A CFD STUDY OF CAVITATION IN REAL SIZE DIESEL INJECTORS
dc.type Tesis doctoral es_ES
dc.identifier.doi 10.4995/Thesis/10251/14723 es_ES
dc.rights.accessRights Abierto es_ES
dc.contributor.affiliation Universitat Politècnica de València. Departamento de Máquinas y Motores Térmicos - Departament de Màquines i Motors Tèrmics es_ES
dc.description.bibliographicCitation Patouna, S. (2012). A CFD STUDY OF CAVITATION IN REAL SIZE DIESEL INJECTORS [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/14723 es_ES
dc.description.accrualMethod Palancia es_ES
dc.type.version info:eu-repo/semantics/acceptedVersion es_ES
dc.relation.tesis 3739 es_ES


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