Our research group has been studying control valves for more than ten years. Thanks to the collaboration with national and international companies, our group can rely on an extended practical experience on hydraulic devices.

Several approaches are used to address the research:

• Numerical analysis through CFD methods;
• Experimental investigations using the Hydraulic Laboratory facilities;
• Conceptual and theoretical analysis.

The research group designed and realized test plants for both compressible and incompressible fluids for standard devices characterization and research.  Together with the experimental tests, numerical analysis through CFD methods has been adopted to fully characterize control devices, extending the experimental data to a wide range of applications. Moreover, using the experimental data to validate the numerical model, CFD permitted us to study particularly complex problems and develop new methods to predict crucial parameters of the devices. 

  

Fluid dynamic characterization

Control valves are devices used to regulate liquid, gas and multiphase flows, controlling specific parameters, such as flow rate, pressure drop and temperature.

On these devices, our research group performs numerical analysis through computational fluid dynamics technics in order to fully characterize their behavior and calculate the efficiency and other parameters used for their application.

The numerical study is complementary to the tests conducted in Fantoli laboratory (Hydraulic Lab G. Fantoli), where a test plant, designed and realized according to the international standards, is available in the control valves section both for research activities and external commissions.

The synergy between experimentation and numerical analysis allows to exhaustively and accurately study the characteristics of many different hydraulic devices, calculating the parameters defined in IEC and ISA standards. The characterization of one device is often followed by a phase of optimization and development of new applicative solutions.

An example of research, where both experimental and numerical studies have been necessary, regards cavitation, a harmful phenomenon for control valves that starting from noise and vibration can bring erosion and pitting of mechanical parts. Our aim has been the development of a method to predict the incipient cavitation number, a parameter that identifies the onset of cavitation, through single-phase flow simulations.

The experimental data have been used to validate the new numerical method and extend its applicability to a wide range of hydraulic devices, such as control valves, orifices, perforated plates, quick connector. 

 

Selected publications 

• Malavasi S., Rossi M.M.A., Ferrarese G., Messa G.V. (2013). Numerical Method to Provide Cavitation Index for Control Valves. In: Proceedings of the ASME 2013 Pressure Vessels & Piping Division Conference PVP2013. p. 1-7, Paris, France, 14/07/2013-18/07/2013
• Malavasi S., Messa G., Fratino U., Pagano A. (2012). On the pressure losses through perforated plates. Flow measurement and instrumentation, vol. 28, pp. 57-66.
• Malavasi S. and Messa G., (2011), Dissipation and Cavitation Characteristics of Single-Hole Orifice.Journal of Fluids Engineering, vol. 133, pp. 1-8.
• Giacomo Ferrarese, Gianandrea V Messa, Marco MA Rossi, Stefano Malavasi, “New method for predicting the incipient cavitation index by means of single-phase computational fluid dynamics model” DOI:10.1177/1687814015575974, vol. 7 no. 3, 1687814015575974

 

Research Projects

• 2015/17 "EPICO Project" - ENI S.p.A.
• 2015/18 "Current Turbines" - SINERGIE INTEGRATE S.r.l.
• 2013 "Numerical study of Pelton turbines performances” – HYDRO ENERGIA S.r.l.
• 2011 “Performance analysis of Control valves” - PIBIVIESSE S.r.l. 
• 2011/14 “Analysis and Developing of Control Valves” - PIBIVIESSE S.r.l.
• 2010/11 “Single & Multistage Choke Valves” - BREDA ENERGIA S.p.a.  
• 2010/11 “Fluid-dynamic analysis of domestic environments” – INDESIT  Company S.p.A. e Fondazione Politecnico. 
• 2008/09 “Choke Valves” - BREDA ENERGIA SpA. 
• 2007/10 “Analysis and Developing of Control Valves” - PIBIVIESSE Srl. 
• 2005/07 “Modelling of control valves” - PIBIVIESSE Srl 
• 2003/04 “Modelling of Cage Ball® control valves” - PIBIVIESSE Srl 

 

Noise prediction

The issue of acoustic emissions is common in all the applications that work with fluids and cannot exceed prescribed noise limits. Common examples of applications are pipelines for oil&gas and industrial plants, in particular when gases are the flowing fluids. Noise is typically produced by the fluctuating quantities generated by the kinetic energy dissipation of vortexes and turbulence after the flow passes a singularity, such as valves and orifices. The analysis of noise emission problems is related with the identification of the source region, the downstream transport, the interaction between the flow and the structure geometry and the external propagation through the walls. Control devices are usually the main source of noise and a correct design is fundamental to immediately reduce noise emissions at the origins and to avoid acoustic insulation expenses.

 Our activities are focused on the development of methodologies and good practices for noise prediction and reduction through experimental and numerical research according to the international standards.

 

Selected publications and MS thesis:

• Fenini L., Bossi F.C., Malavasi S., 2016, Broadband Noise Generated Downstream of a resistor in a duct, Proceedings of 11° FIV conference, The Hague, The Netherlands
• Bossi F.C., Malavasi S., 2014, Acoustic analysis of a rotary control valve. Proceedings of the ASME 2014 Pressure Vessels and Piping Conference, Anaheim, California
• Malavasi S., Bossi F.C., 2012, Experimental analysis of aerodynamic noise generation in a rotary control valve. Proceedings of the 10^th International Conference on Flow-Induced Vibration (& Flow-Induced Noise), Dublin, Ireland, pp. 697-703 
• Fenini L., 2015, Analisi di un modello numerico per la previsione del rumore generato da un piatto forato, MS Thesis in Mathematical Engineering, Politecnico di Milano, Milano, Italy (in Italian)
• Mazzaro G., 2014, Rumore fluidodinamico in dispositive di regolazione. MS Thesis in Civil Engineering, Politecnico di Milano, Milano, Italy (in Italian)
• Oldani L., 2014, Implementazione di un modello per la previsione dell’emissione acustica in dispositivi di regolazione. MS Thesis in Mathematical Engineering, Politecnico di Milano, Milano, Italy (in Italian)

 

Research Projects

• 2015/2018 "Modeling and Prediction of the aerodynamic noise in control devices", Ph.D. scolarship funded by PIBIVIESSE S.r.l.