“COMPARATIVE ANALYSES OF MICRO-PARTICLE IMPACT BETWEEN TRANSONIC AND SUBSONIC AXIAL COMPRESSORS”

“COMPARATIVE ANALYSES OF MICRO-PARTICLE IMPACT BETWEEN TRANSONIC AND SUBSONIC AXIAL COMPRESSORS”

Solid micro-particle ingestion is one of the principal degradation mechanisms in compressor sections. In particular, in industrial applications, micro-particles not captured by the air filtration system cause fouling and, consequently, a performance drop. This paper presents three-dimensional numerical simulations of micro-particle ingestion (0.15 – 2.00) µm on axial transonic and subsonic compressor rotors. The mass flow rate swallowed by the two rotors is comparable and represents the basis for the fouling comparison. The results show that particles tend to follow the flow by impacting on blade tips with a higher concentration on the…Continua a leggere

“CFD study on special duty centrifugal pumps operating with viscous and non-Newtonian fluids”

Centrifugal pump design operating with special fluids (high viscosity, non-Newtonian, solid handling) is usually performed by considering water as the working fluid and then by applying empirical correction to the performance according to the fluid processed. CFD techniques allow the analysis of the impact of the fluid properties and the effectiveness of the design correction, rather than only relying on specific empirical data for each specific fluid. In this paper, a CFD analysis is performed on a large-size industrial food processing centrifugal pump originally designed for tomato paste. A model sensitivity analysis on…Continua a leggere

“A numerical study on special duties centrifugal pumps: sensitivity analysis of CFD models for high viscous and non-Newtonian fluids”

Special duties rotordynamic pumps operates with non-water fluids. They have many advantages over volumetric pumps (like wider range of operative flow rates, less friction problems, etc…) so they could find a wide approval in low viscosity non-Newtonian fluid applications. High viscous and non-Newtonian fluids are extensively used in many industrial processes, in particular in Oil and Gas applications (i.e. slurries, oil, betonites, suspensions, etc). Other field of interest for high viscous and non-Newtonian fluids include the food processing industry (tomato paste, fruit juices, etc…) and pharmaceutical applications (i.e. tooth paste, cosmetics, etc…). These…Continua a leggere
“A numerical method for the efficient design of free opening hoods in industrial and domestic applications”

“A numerical method for the efficient design of free opening hoods in industrial and domestic applications”

In this paper, a numerical method for the design of free opening hoods in industrial and domestic applications is presented. The method is based on a CFD (Computational Fluid Dynamics) formulation for the capturing velocity assessment in capturing hoods which account for geometrical and viscous effects. Different hoods, which differ in shape (square and rectangular) and size, are created and their velocity field determined numerically. A comparison between the obtained numerical results and results obtained from empirical formula found in literature are presented and the discrepancy between them highlighted. Then, starting from the…Continua a leggere

“Cross-Validation of Multistage Compressor Map Generation by means of Computational Fluid Dynamics and Stage-Stacking Techniques”

Gas turbine operating state determination consists of the assessment of the modification, due to deterioration and fault, of performance and geometric data characterizing machine components. One of the main effects of deterioration and fault is the modification of compressor and turbine performance maps. In this paper, three-dimensional numerical simulations of a multistage axial compressor are carried out. As a case study, the axial sections (i.e. the first six stages) of the Allison 250-C18 axial-centrifugal compressor are considered for the numerical investigation. Simulations are performed by means of a commercial computational fluid dynamic code.…Continua a leggere
“Numerical simulation of evacuated tube solar water heaters”

“Numerical simulation of evacuated tube solar water heaters”

This paper evaluates the characteristics of water-in-glass evacuated tube solar water heaters including assessment of the circulation rate through single ended tubes. A numerical model of the fluid flow inside a single ended evacuated tube has been developed assuming no interaction between adjacent tubes in the collector array. The numerical model is firstly validated by means of literature data. Then, the performance in terms of circulation mass flow rate in different heat flux condition and at different inclination angle of the collector are evaluated. Moreover, a sensitivity analysis on the effect of the…Continua a leggere