gunt ET 796 User manual

Experiment Instructions
ET 796 Gas Turbine Jet Engine

ET 796 GAS TURBINE JET ENGINE
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All rights reserved, G.U.N.T. Gerätebau, Barsbüttel, Germany 08/2014
This manual must be kept by the unit.
Before operating the unit:
- Read this manual.
- All participants must be instructed on
handling of the unit and, where appropriate,
on the necessary safety precautions.
Version 0.1 Subject to technical alterations
Experiment Instructions
Last modification by: Dipl.-Ing. J.Boxhammer

ET 796 GAS TURBINE JET ENGINE
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All rights reserved, G.U.N.T. Gerätebau, Barsbüttel, Germany 08/2014
Table of Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2 Safety. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1 Intended use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2 Structure of safety instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.3 Safety instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.4 Ambient conditions for the operating and storage location . . . . . . . . 12
3 Description of the device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.1 Design of the trainer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.2 Device design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.3 Process schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.4 Components of the trainer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
3.4.1 Gas turbine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
3.4.2 Fuel system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.4.3 Starting and ignition system . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.4.4 Control elements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
3.5 Measurement data acquisition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
3.5.1 Program installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
3.5.2 Program operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
3.6 Setting up the gas turbine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
3.6.1 Checking the gas turbine . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
3.6.2 Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
3.7 Operating the gas turbine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
3.7.1 Preparations for start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
3.7.2 Bleeding the fuel lines with the kerosene start system . . . . . 33
3.7.2.1 Switch ECU to 6V kerosene start mode. . . . . . . . . . . . . . . . 33
3.7.2.2 Bleeding the fuel supply to the engine: . . . . . . . . . . . . . . . . . 34
3.7.2.3 Bleeding the fuel supply to the kerosene start system: . . . . 35
3.7.2.4 Testing and adjusting the fuel pump power . . . . . . . . . . . . . 37

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3.7.3 Starting the gas turbine up . . . . . . . . . . . . . . . . . . . . . . . . . . 39
3.7.4 Operating the gas turbine . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
3.7.5 Shutting down the gas turbine . . . . . . . . . . . . . . . . . . . . . . . 42
3.8 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
3.8.1 Glow plug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
3.8.2 Servicing the gas turbine . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
3.9 Faults and troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
3.10 Decommissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
4 Basic principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
4.1 The open gas turbine cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
4.1.1 Representation in the heat diagram . . . . . . . . . . . . . . . . . . . 49
4.1.2 Thermal efficiency (ideal) . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
4.1.3 Specific work capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
4.1.4 Representation in the p-v diagram . . . . . . . . . . . . . . . . . . . . 52
4.1.5 Gas turbine jet engine. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
5 Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
5.1 Recording measurements and their subsequent evaluation . . . . . . . 55
5.1.1 Preparation for the experiment . . . . . . . . . . . . . . . . . . . . . . . 55
5.1.2 Conducting the experiment. . . . . . . . . . . . . . . . . . . . . . . . . . 56
5.1.3 Measured values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
5.1.4 Analysis of the experiment . . . . . . . . . . . . . . . . . . . . . . . . . . 57
5.1.4.1 Air mass flow and fuel mass flow . . . . . . . . . . . . . . . . . . . . . 57
5.1.4.2 Other characteristics of the gas turbine . . . . . . . . . . . . . . . . 59
5.1.4.3 Representation of the measured data in diagrams. . . . . . . . 61
5.1.4.4 Determining the fuel-air ratio . . . . . . . . . . . . . . . . . . . . . . . . 66
6 Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
6.1 Technical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
6.2 List of abbreviations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
6.3 List of formula symbols and units . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
6.4 List of symbols in the process schematic . . . . . . . . . . . . . . . . . . . . . 73

ET 796 GAS TURBINE JET ENGINE
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All rights reserved, G.U.N.T. Gerätebau, Barsbüttel, Germany 08/2014
6.5 List of identification letters used in the process schematic . . . . . . . . 74
6.6 Tables and graphs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
6.7 Worksheets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

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ET 796 GAS TURBINE JET ENGINE
1 Introduction 1
All rights reserved, G.U.N.T. Gerätebau, Barsbüttel, Germany 08/2014
1 Introduction
The ET 796 trainer is used to demonstrate and
study the function and behaviour of a gas turbine
in the model scale. Gas turbine plants are used to
generate mechanical and electrical energy:
– Driving generators in power plants
– Driving compressors and pumps in oil and gas
extraction
– Propulsion of ships, locomotives and heavy
vehicles
– For aircraft propulsion with propeller and jet
engines
Gas turbines are always used where high concen-
tration of power, low weight and quick startup are
required. Unlike piston engines, being turboma-
chines they allow high material throughputs with
small dimensions. This means lightweight yet
powerful drives can be constructed.
Since the moving parts of a gas turbine only per-
form a rotary movement, with good balance it is
possible to achieve virtually vibration-free run-
ning. The loud noise emissions caused by the
high gas velocities and by contact with the atmos-
phere are a drawback.
Compared to steam turbines, gas turbines oper-
ate at higher temperatures but at lower pressures.
The high temperatures, especially in the area of
the gas turbine, require special heat-resistant
materials.
The gas turbine used in the trainer is a single-
shaft gas turbine. All components required for
operation of the system are compactly combined
in a mobile rack.
Fig. 1.1 J85-GE-17A turbojet engine
from General Electric
Fig. 1.2 JetCat gas turbine

ET 796 GAS TURBINE JET ENGINE
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The system has a simple construction and is
designed specifically for educational purposes.
The operation and display of all important process
parameters is summarised on a control panel.
The PC-based measurement data acquisition
with evaluation software allows online logging of
all relevant process variables and their graphical
representation.
Besides purely demonstrating the turbine's oper-
ational behaviour, it is also possible to undertake
qualitative studies such as determining the thrust
and other characteristics of the gas turbine.
Learning objectives / exercises
• Operating behaviour of a jet engine including
starting procedure
• Determining the specific thrust
• Determining the specific fuel consumption
• Determining the fuel-air ratio