HYDRAULICS
H39D - Francis Turbine Study Unit - Code 933400
1. General
Didacta's H39D study unit has been designed for a complete range of tests on Francis type hydraulic turbines.
The unit is perfectly self-sufficient, takes up little space and can be easily moved.
The H39D is fitted with a special "VISIFLOW' version turbine featuring a number of transparent parts which make it possible
to see very clearly the hydrodynamic phenomena taking place inside it.
The turbine is coupled to the SUD10D dynamometric braking unit which makes it possible to determine the torque and power
characteristics of the turbine.
When the unit is used in conjunction with the data acquisition and analysis system for personal computer called SAD/H39D
it proves possible to take the measurements automatically, to plot the curves on screen or print them out, to store the
experimental data on disk or print them. The SAD/H39D system is described in a separate data sheet.
The unit is supplied with manuals which describe all parts of the trainer, the installation and utilisation procedures, as well as
many exercises with the relative results.
2. Composition
The H39D Study Unit consists of:
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VISIFLOW Francis Turbine
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3 kW SUD10D dynamometric braking unit
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12.5 HP centrifugal electric pump
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100 m3/h flowmeter
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No. 2 0.4 bar pressure gauges
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-1, +0.6 bar mano-vacuum meter
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-1.0 bar vacuum meter
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400 lt. supply tank
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Power supply and control electric panel
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Optional stroboscope (Code 901521)
DIDACTA Italia S.r.l. - Strada del Cascinotto, 139/30 - 10156 Torino - Italy
Tel. +39 011 2731708 - Fax +39 011 2733088 - http://www.didacta.it - E-mail: info@didacta.it
3. Description
The hydraulic circuit (see fig. 1) essentially consists of a low-head, high-flow centrifugal pump, a flow meter, two pressure
gauges, the turbine with the transparent end shield, a supply tank and the connecting pipes.
The purpose of the system is to enable the students to work out the power and torque curves of a Francis turbine.
An electrically operated centrifugal pump transfers the water under pressure from the main tank to the turbine, simulating the
low drop and high flowrate conditions as are typical of Francis turbines.
The system is equipped with a system to adjust the incidence of guide blades during turbine operation, with an opening
control hand-wheel which is convenient and easy to use.
A dynamometric unit with a digital rev counter and a torque read-out on a luminous scale is coupled to the turbine shaft and
makes it possible to determine the torque and power characteristics.
The rotation speed, pressure, flowrate, voltage and current values are processed in succession so as to determine head and
power, torque and efficiency of the turbine. By plotting these values we get the torque and power curves of Francis turbines.
The metal structure of welded steel is extremely strong and the finishing is achieved by means of abrasion resistant, epoxy
type paint.
All the parts that come in contact with the water are made of stainless materials.
A stroboscope, available as an option, makes for a clearer visualisation of the hydraulic phenomena taking place in the
turbine body.
4. Technical specifications
VISIFLOW Francis Turbine
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Aluminium scroll with stainless interior
Scroll diameter 600 mm
9 blade bronze impeller, 140 mm diameter with labyrinth seal
10 vane aluminium distributor, 195 mm diameter, external opening control
Discharge head and two windows of transparent material on the scroll body to make it possible to observe the position
of the guide vanes from the outside
Max. flowrate of 120 m3/h
Max. head: 20 m water column
Rotation speed: max. 2300 rpm
Efficiency 25 - 30 %
Power greater than 1 kW
Centrifugal electric pump
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Power 12.5 HP
Max. flowrate 2000 lt./min
Max. head: 30 m water column
Rotation speed 2900 rpm at 50 Hz
SUD10D Dynamometric braking unit
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Power 3 kW
5. Experiments
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Visualisation of fluid motions in the turbine body around the guide vanes on the impeller and the discharge diffuser
cone.
Plotting the characteristic curve of the turbine's runaway speed for different blades opening as a function of rotation
speed.
Plotting the characteristic curves of torque at the machine shaft as a function of rotation speed for different constant
values of head and blades opening.
Plotting the characteristic curves of power delivered to the shaft as a function of rotation speed for different blades
opening.
Plotting the characteristic curves of hydraulic supply power as a function of rotation speed for different blades opening.
Plotting the machine efficiency curves as a function of rotation speed for different blades opening.
Plotting the iso-efficiency curves on a diagram as a function of flowrate and turbine rotation speed
Plotting flowrate curves as a function of rotation speed with constant head, and for different blades opening.
6. Required services
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Electrical power supply: 380 V A.C. 3F+N, 50/60 Hz, 10 kW
7. Weights and dimensions
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Dimensions: 1650 x 1120 x 2100 h mm
Weight: empty 850 kg, with load 1170 kg
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Fig. 1 - General Synoptic
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Feeding tank
Vacuum pressure gauge
Centrifugal pump
Pressure gauge
Flow rate meter
Pressure gauge
Francis Turbine
Hand wheel for distributor blade control
Coupling joint
Generator-brake SUD10D
SAD/H39DAutomatic Data Acquisition System for H39D
1. General
The system enables to perform the experiments relating the
Didacta H39D - Francis Turbine Study Unit by means of an IBM
compatible Personal Computer.
It is possible to automatically acquire the quantities required for the
tests (turbine inlet pressure Pm, differential pressure Dp for the
flow rate Q measurement, torque at turbine shaft T, speed n) and
to process them in order to obtain the characteristic data and
diagrams which allow to better understand the behaviour of the
turbine under different actual operating conditions.
The system is supplied with an instruction manual which describes
the technical features of the system (hardware and software),
explains how to set-up and calibrate the data acquisition system,
suggests several exercises and gives sample experimental data
and diagrams.
2. Composition
The system is composed of:
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Electronic Transducers Kit, complete with Feeding Unit and Signal Conditioning Electronics and A/D Conversion Unit
(Code 933412).
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Acquisition and Analysis Software for Windows (Code 914315).
3. Description
Electronic transducers kit complete with Feeding Unit and Signal Conditioning Electronics and A/D Conversion Unit
(Code 933412)
The kit is composed of:
• Differential pressure Dp electronic transducers with calibrated diaphragm to measure the main flow rate Q, fitted with
digital indicator and signal transmitter.
• Pressure electronic transducer to measure the turbine inlet pressure Pm, fitted with signal transmitter.
• Signal converter for the strength-gauge transducer (fitted to the basic assembly) to measure the torque T at turbine shaft.
• Signal converter for the electronic angular speed transducer (fitted to the basic assembly) to measure the rpm speed n.
The Feeding Unit and Signal Conditioning Electronics allow the conversion of the signals supplied to standard signals,
suitable for the A/D Conversion card. The A/D Conversion card operates on 12 bit with a sampling frequency of about 10
kHz.
The unit can be connected to an IBM or compatible Personal Computer through the serial RS-232 port.
Data Acquisition and Analysis Software (Code 914315)
The Acquisition and Analysis Software operates under MS-Windows and allows to acquire data from the transducers located
on the plant and to calculate other parameters from the acquired data.
The software allows to display on the screen or to print the diagrams of the acquired data as a function of time and the
diagrams required in the exercises. Acquired and calculated data can be saved onto disk in ASCII format.
Besides it is possible to carry out simulations by introducing data through keyboard.
4. Minimum PC Configuration Required
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PC minimum Pentium with Hard Disk (>10Gb) and CD drive, SVGA graphic card 800x600, mouse, RAM 32 MB, USB
port;
XPMS-Windows or later versions;
Graphic Printer.
5. Weight and Dimensions
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Dimensions: 540 x 350 x 200 h mm
Weight: 15 kg
Cod. R00181/E 1008 Ed. 01 Rev. 02
In any time and without notice, Didacta Italia can carry out any appropriate modification on the product details, always
maintaining their main features, according to the designing and teaching necessity.
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