Search results for "Cross-Flow"
showing 10 items of 20 documents
Banki-Michell Optimal Design by Computational Fluid Dynamics Testing and Hydrodynamic Analysis
2013
In hydropower, the exploitation of small power sources requires the use of small turbines that combine efficiency and economy. Banki-Michell turbines represent a possible choice for their simplicity and for their good efficiency under variable load conditions. Several experimental and numerical tests have already been designed for examining the best geometry and optimal design of cross-flow type machines, but a theoretical framework for a sequential design of the turbine parameters, taking full advantage of recently expanded computational capabilities, is still missing. To this aim, after a review of the available criteria for Banki-Michell parameter design, a novel two-step procedure is de…
ESPERIENZE FLUIDODINAMICHE SU UNA TURBINA DI PICCOLA POTENZA TIPO BANKI-MICHELL
2012
Numerical and experimental investigation of a cross-flow water turbine
2016
ABSTRACTA numerical and experimental study was carried out for validation of a previously proposed design criterion for a cross-flow turbine and a new semi-empirical formula linking inlet velocity to inlet pressure. An experimental test stand was designed to conduct a series of experiments and to measure the efficiency of the turbine designed based on the proposed criterion. The experimental efficiency was compared to that from numerical simulations performed using a RANS model with a shear stress transport (SST) turbulence closure. The proposed semi-empirical velocity formula was also validated against the numerical solutions for cross-flow turbines with different geometries and boundary c…
RECUPERO ENERGETICO ALL’INTERNO DELLE RETI ACQUEDOTTISTICHE MEDIANTE MICROTURBINE IDRAULICHE
2022
Low-Head Hydropower for Energy Recovery in Wastewater Systems
2022
Hydraulic turbines for energy recovery in wastewater treatment plants, with relatively large discharges values and small head jumps, are usually screw Archimedes or Kaplan types. In the specific case of a small head jump (about 3 m) underlying a rectangular weir in the major Palermo (Italy) water treatment plant, a traditional Kaplan solution is compared with two other new proposals: a Hydrostatic Pressure Machine (HPM) located at the upstream channel and a cross-flow turbine (CFT) located in a specific underground room downstream of the same channel. The fluid mechanical formulations of the flow through these turbines are analyzed and the characteristic parameters are stated. Numerical ana…
Costruzione e sperimentazione di una turbina cross-flow per acquedotti
2014
La memoria descrive una nuova micro turbina idraulica con capacità di regolazione della portata, per installazioni in piccoli corsi d’acqua, su acquedotti esistenti o a valle di impianti di depurazione delle acque. Viene inoltre descritta l’installazione del prototipo della turbina nella rete idropotabile di un comune siciliano.
Assessment of cross-flow filtration as microalgae harvesting technique prior to anaerobic digestion: Evaluation of biomass integrity and energy demand
2018
[EN] In the present study, the effect of cross-flow filtration (CFF) on the overall valorization of Chlorella spp. microalgae as biogas was assessed. The effect of CFF on microalgae cell integrity was quantified in terms of viability which was correlated with the anaerobic biodegradability. The viability dropped as the biomass concentration increased, whereas anaerobic biodegradability increased linearly with the viability reduction. It was hypothesized that a stress-induced release and further accumulation of organic polymers during CFF increased the flux resistance which promoted harsher shear-stress conditions. Furthermore, the volume reduction as the concentration increased entailed an …
DEVIATORE DI FLUSSO PER TURBINE IDRAULICHE IN LINEA
2021
Un deviatore di flusso per una turbina idraulica a flusso incrociato presenta una sezione di uscita atta ad essere collegata alla sezione a valle della condotta idraulica per l’immissione di un flusso in uscita del fluido liquido in pressione con un vettore di velocità di uscita avente modulo di uscita (Vo) e direzione di uscita (do) predeterminati, un condotto di scarico per il ripristino del vettore velocità di detto flusso in uscita al modulo in ingresso ed a una direzione di uscita sostanzialmente parallela o coincidente con detta direzione di ingresso (di), in cui detto deviatore comprende, un primo settore immediatamente a valle di detta girante ed atto a variare la direzione del flus…
A New Cross-Flow Type Turbine for Ultra-Low Head in Streams and Channels
2023
In the last few decades, hydropower production has been moving toward a new paradigm of low and diffused power density production of energy with small and mini-hydro plants, which usually do not require significant water storage. In the case of nominal power lower than 20 kW and ultra-low head H (H < 5 m), Archimedes screw or Kaplan type turbines are usually chosen due to their efficiency, which is higher than 0.85. A new cross-flow type turbine called Ultra-low Power Recovery System (UL-PRS) is proposed and its geometry and design criteria are validated in a wide range of operating conditions through 2D numerical analysis computed using the ANSYS Fluent solver. The new proposed solution…
REGOLAZIONE DELLE PRESSIONI MEDIANTE PRODUZIONE DI ENERGIA IDROELETTRICA NELLE RETI DI DISTRIBUZIONE IDRICA
2016
Negli ultimi anni, sempre più gestori di reti idriche hanno mostrato interesse nella realizzazione di micro e mini centrali idroelettriche poiché: È spesso disponibile un eccesso di pressione che viene oggi, frequentemente, dissipato mediante valvole PRV; La produzione di energia elettrica “propria” contribuirebbe a ridurre i costi energetici per la gestione della rete stessa