Parametrització d'una bomba d'engranatges externs i validació en condicions reals
(English) Pumps of positive volumetric displacement (PDVP) drive a volume of fluid from suction to discharge for each revolution of its shaft, called derived capacity, and therefore, in an ideal constant capacity pump the flow rate is proportional to the rotation speed and independent of the working...
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| Formato: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2023 |
| País: | España |
| Recursos: | CBUC, CESCA |
| Repositorio: | TDR. Tesis Doctorales en Red |
| OAI Identifier: | oai:www.tdx.cat:10803/689599 |
| Acesso em linha: | http://hdl.handle.net/10803/689599 https://dx.doi.org/10.5821/dissertation-2117-398695 |
| Access Level: | acceso abierto |
| Palavra-chave: | Bomba engranatges externs (BE) Modelització amb Bond Graph Plaques laterals flotants Coeficients de pèrdues Proves experimentals de laboratori i de camp Caracterització de les prestacions d’una BE en condicions reals Parametrització experimental segons normes ISO Pump external gears (BE) Experimental parameterization according to ISO standards Modelling with Bond Graph Floating side plates Loss coefficients Experimental laboratory and field tests Characterization of the benefits of a BE in real conditions Àrees temàtiques de la UPC::Enginyeria mecànica 621 |
| Resumo: | (English) Pumps of positive volumetric displacement (PDVP) drive a volume of fluid from suction to discharge for each revolution of its shaft, called derived capacity, and therefore, in an ideal constant capacity pump the flow rate is proportional to the rotation speed and independent of the working pressure. This characteristic makes them very suitable to be used in oleo-hydraulic energy transmission systems (STEO). In a non-ideal pump, the flow losses due to leaks and the torque losses due to friction must be considered, evaluated through ISO experimental tests. With these results can be made a parameterization of pump behaviour in a permanent regime (average flow and average torque depending on the operating conditions) as well as its pulsating behaviour (flow ripple superimposed on the average flow as an intrinsic consequence of the pumping mechanism). The first part of the Thesis has been dedicated to this experimental parameterization. There are no precedents for any verification if this parameterization carried out with laboratory data and the consequent modelling is sufficient to predict the behaviour of these hydrostatic units in real working conditions. This validation has been the main objective of the second part of the Thesis. As part of the BRITE "ECOPUMP" project, multiple external gear pumps (EGP) have been tested, and a reference pump of this type has been chosen to carry out the study. It is first of all to get to know in depth the operation of this type of pump, in order to have the necessary criterion to interpret the subsequent results. Next, all the experimental tests were carried out to perform the parameterization and modelling of its behaviour. Finally, experimental field tests have been carried out in real work cycles that allow the measured data to be compared with the results of the model under the same operating conditions. However, the EGP have a simple construction, the mechanism for compensating the axial clearance between the floating bushing plates and the gears is the key to their behaviour. Therefore, to interpret the discrepancies between the measured data in the field tests and the results of the simulation, it is essential to study the dynamics of these plates. A tool is needed that allows simultaneous monitoring this movement together with the behaviour of the pump, and therefore, a model of the plate dynamics that can be integrated into the pump model. The Bond Graph technique is very suitable for this purpose. A tool has been created that allows simulate in real time long work cycles with a conventional computer, without using complex CFD software. Emphasize the use of the analogy of analytical solutions of hydrodynamic bearings with lubrication in the studied domain. The dimensional analysis has led us to use expressions that, to be valid, must be adjusted with experimental results that relate the movement of the plates to the operating conditions of the pump. It is demonstrated how the parameterized model is fully valid to know the behaviour of the pump as long as the operating conditions do not suffer sudden changes. Otherwise, the dynamics to reach the axial clearance balance of the compensation mechanism explains peculiar behaviours which could not have been analysed without the developed tools. The main results of this research have been presented in various papers of Torrent et al., having established an unprecedented methodology applicable to any other type of BDVP. |
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