MR-HM 150.20 Operating principle of a Francis turbine Teaching Equipment Hydraulic Bench Description • model of a reaction turbine • transparent operating area • turbine with adjustable guidevanes • loading by band brake Water turbines are turbomachines utilising water power. The Francis turbine isa type of reaction turbine which converts the pressure energy of the waterinto kinetic energy in the distributor andin the rotor. The water is fed in the distributor by means of a spiral housing. The flowing water is accelerated in thedistributor by the adjustable guide vanesand directed onto the blades. The redirection and further acceleration of thewater in the rotor generates an impulsewhich is transmitted to the rotor. MR-HM 150.20 is the model of a Francisturbine demonstrating the function of areaction turbine. The experimental unit consists of the rotor, the distributor with adjustable guidevanes, a band brake for loading the turbine and a housing with a transparentfront panel. The transparent cover enables to observe the water flow, the rotor and the guide vanes during operation. The angle of attack and thus the power of the rotor are modified by adjusting the guide vanes. The turbine torque is determined byforce measurement on a band brakeand is read on spring balances. Formeasuring the rotational speed, a noncontact speed sensor, e.g. MR-HM 082, isrequired. A manometer shows the water pressure at the turbine inlet. The experimental unit is positioned easily and securely on the work surface ofthe MR-HM 150 base module. The water issupplied and the flow rate measured byMR-HM 150. Alternatively, the experimentalunit can be operated by the laboratorysupply. Learning objectives/experiments • design and function of a Francis turbine • determination of torque, power and efficiency • graphical representation of characteristic curves for torque, power and efficiency Specification [1] function of a Francis turbine [2] transparent front panel for observing the operatingarea [3] loading the turbine by use of the band brake [4] adjustable guide vanes for setting different anglesof attack [5] marking on brake drum for non-contact speedmeasurement [6] instruments: spring balances for determining thetorque, manometer shows pressure at turbine inlet [7] flow determination by base module MR-HM 150 [8] water supply using the base module MR-HM 150 or vialab supply Technical data Turbine • output: 12W at n=1100min-1, approx. 40L/min,H=8m • rotor · 7 blades · blade width: 5mm · external Ø: 50mm • guide vanes · 6 vanes, adjustable (20 stages) Measuring ranges • force: 2x 0…10N • pressure: 0…1,0bar LxWxH: 400x400x630mm Weight: approx. 17kg Required for operation MR-HM 150 (closed water circuit) or water connection,drain Scope of delivery 1 experimental unit 1 set of instructional material
