Axial Turbine Brochure

For heads between 1 and 30 m, Mhylab has developed hydraulic profiles of axial Kaplan-type turbines devoted to small hydropower through laboratory tests. Based on the principles of similitude and systemisation (in oppo-sition with standardisation), Mhylab designs the turbine specific to each low-head site, while guaranteeing its performance and an optimal hydrodynamic behaviour regarding cavitation.With the objective of integration into any type of sites, as refurbished power plants equipped with Francis turbines, multipurpose schemes, as the ones using drinking water, new run-of-the-river plants, different settings are available, that respect the homology with the scale model.Axial Kaplan-type turbinesmhylab mini-hydraulics laboratoryOperating rangeNet head between 1 and 30 mNominal discharge between 0.075 and 10 m3/s1 Axial turbine set on Mhylab’s test bench, with a vertical axis2 Axial turbine with a vertical axis at Garbet plant in Oust (F) (Q = 3.2 m3/s, Hn = 16.6 m, 6 blades, external runner diameter: 900 mm, 500 rpm, 478 kW)3 Axial turbine with a horizontal axis at Poggio Cuculo plant, using the drinking water of Arezzo (I) (Q = 0.380 m3/s, Hn = 18.3 m, 8 blades, external runner diameter: 314 mm, variable speed, 60 kW)4 Axial turbine with a horizontal axis at St Bueil plant (F) (Q = 1.5 m3/s, Hn = 28 m, 8 blades, external runner diameter: 580 mm, 1000 rpm, 370 kW)1 2 34Casing including the speed increaser and the generatorStraight draft tubeInlet for a homogeneous flow upstream from the runnerFixed guide vanesRunner with 4 moveable or fixed bladesDownstream butterfly valve as security deviceWater chamber turbineNet head between 1.5 and 5 mUpstream water levelSaxo turbineNet head between 5 and 30 mInlet, composed of a square-section elbow and three guide vanes. It combines manufacture simplicity, optimal flow distribution and a simple setting of the generator shaft.Guide vane system composed of 12 fixed vanes. It gives the flow an optimal direction to the runner blades. Runner with 4 to 8 adjustable or fixed blades.Draft tube designed to recover a maximum of kinetic energy, while guaranteeing a homogeneous outlet flow. It is equipped with a security downstream valve (butterfly or sluice gate). The Saxo turbine fits especially small hydropower sites, thanks to its reduced horizontal dimensions and its simple manufacturing, in comparison with a spiral casing. The characteristic of this turbine is its large operating range regarding discharges and net heads at high efficiencies and without damage due to cavitation.Downstream water levelThis turbine design is characterised by two simplifi-cations: 1. concerning the civil works, as the machine is set directly on the weir, 2. concerning the turbine manufacturing. This results in a reduction of the investment, improved by the absence of valves, and an easy maintenance.1 Two axial siphon-type with a vertical axis at the UMV plant in Vallorbe (CH) (Q = 2.5 m3/s per machine, Hn = 2.0 m, 4 blades, externalrunner diameter: 1250 mm, 146 rpm, 76 kW)Parameters adjustable to the site infrastructure:1. Inlet of the turbine: a. penstock, b. water chamber or square section inlet for sites with a head lower than 5 m, composed of an upstream water basin,c. siphon inlet with a setting on the weir, for sites with a head below 3.5 m2. Turbine axis: vertical, horizontal or inclined3. Angle of the elbow of the upstream inlet4. Straight or bent draft tubeSiphon turbineNet head between 1.0 and 3.5 mDraft tube, without any valve, as the security is guaranteed by the electrovalveSoundproof casing including the generator, the frequency convertor and the vacuum pumpMax. water levelDownstream water levelMin. water levelWeir wallElectrovalve to break the vacuum and stop the turbine in case of emergencyInlet for a homogeneous flow upstream from the runnerRunner with 4 adjustable or fixed blades1MhylabMini-hydraulics laboratoryChemin du Bois Jolens 6 CH-1354 Montcherand T +41 24 442 87 87 F +41 24 441 36 54info@mhylab.com www.mhylab.com www.smallhydro.chPico-turbineNet head between 1.0 and 3.0 mOutput between 1 and 10 kWSoundproof casing including the electrical machine (asynchronous engine or with permanent magnet) for an isolated operation.This type of installation allows mass production, while keeping parameters adjustable to each site (blade opening, rotation speed, length of the draft tube) in order to reach high performances, reliability and cost efficiency.Simplified security downstream valveStraight draft tubeRunner with 4 fixed blades (no discharge regulation), from mass productionWater chamberSteady upstreamwater levelMin. water levelMin. water level?Z = 2 m?Z = 4 m