New MAN TURBO test bed for
turbomachinery and gas turbines
A few years ago, the three turboma-chinery and gas turbine manufactu-ring shops of MAN TURBO sited on different locations, were combined into one entirely new, state-of-the-art fabrication shop. The three for-mer test beds were likewise com-bined into one for better integration into the works structure and com-missioned in the year 1986 (Figs. 1 and 2).
Installation of an additional gas tur-bine test bed became necessary after MAN TURBO acquired the gas turbine programme from the French firm Hispano Suizaas well as en-tering into a cooperation agreement with the American firm Turbo Power and Marine Systems, Inc. (TP&M), a subsidiary of United Technologies. THM 1203 (5.6 MW) and THM 1304 (9.25MW) - two double-shaft gas turbines of Hispano Suiza - are now being completely fabricated and tested under full load in the new work-shops of MAN TURBO.
In collaboration with TP&M, MAN TURBO is currently developing a three-stage power turbine in the triple-shaft 25 MW gas turbine class, for driving production machines. Based on its nominal driving speed of 5500 rpm, the power turbine is designated FT8-55. An industrialized version of the tried-and-tested aero-engine JT8D servesas a gas genera-tor.
In future, the gas turbine FT8-55 as well as the 25 MW gas turbines for generator operation, FT8-30 (3000 rpm) and FT8-36 (3600 rpm), will
also be fitted with peripheral equip-ment in the MAN TURBO workshops and tested under full load condi-tions. Both the gas turbine work-shop and the test bed are fully equipped for this purpose.
Both single machines such as steam turbines, compressors and gas tur-bines and complete machine trains can be tested on the new MAN TURBO test beds where attention is mainly focussed on demonstrating mechanical functions and thermo-dynamic behaviour of the machines. These shop tests - which are exten-sive and wide-ranging - form a vital link in the chain of quality assurance measures accompanying the pro-ducts in every phase of fabrication. The run up to and performance of these tests are followed with great interest by our clients and their inspecting agencies. In particular, our high-performance test beds, equipped with technologically ad-vanced equipment, and operated by highly experienced staff, ensure that the tests satisfy the most stringent demands of our customers. The new test beds at MAN TURBO are spread over an area of about 2200 sq.m, corresponding to about 10% of the overall area of the new fabrication shops, and are located adjacent to the erection and ship-ping bay. The size of the test bed area is based on our experience of two decades in testing of single machines, machine trains and their ancillary units. It also takes account of the bill of quantities and the type and number of the machines to be fabricated.
which ensures that all the testing requirements of the clients are reliably met.
The spectrum of the tests performed by us covers simple mechanical test runs, in which the machines are tested under conditions more or less dissimilar to their later use, including testing up to the maximum admissi-ble speed, which is generally the tripping speed, as also full-load testing of multi-cased turbomachin-ery including ancillary units. Quite often we test machines under conditions very similar to their later use. These tests are designed to establish in particular the suction flow volumes, pressure ratios, stabi-lity limits, efficiencies and coupling
Fig. 2: Layout of the turbomachinery testbed
The vicinity of the test beds of the erection and shipping bay helps to minimize the handling distance. Operating on a three-shift basis, the test beds are fitted with extensive noise-abating equipment designed to meet the statutory noise regula-tions.
Reasons for shop testing
MAN TURBO subject their machines to extensive shop tests prior to ship-ment for a variety of reasons. The trial runs have also to meet stringent demands in terms oft the later pro-duction environment of themachine, quality specifications of the client as well as the experience gained in testing similar machines. Every so often, we are awarded orders by virtue of our test bed performance
power over a large operating range with varying speeds and/ or guide vane positions since, in many cases, the actual field conditions do not offer any opportunity for conducting such tests. The significance of these tests is highlighted by the fact that at times they provide the only basis for assessing the combined opera-tion of machines and the machine trains into which they will later be integrated. On top of that, the test runs also provide an assessment of the boundary values the machine is capable of achieving in later opera-tion as well as providing suitable data for the possible extension of the machine train capacity. Another reason why the testing of complete machine trains including ancillary units and related control and safety systems is performed in the manufacturer's works is that by doing so the duration of field com-missioning can be reduced very con-siderably since the control functions of all the peripheral equipment can be set and matched simultaneously on the testbed in advance.
The test conditions and procedures are laid down in standards such as DIN 1943, VDI 2045, ISO 2314 as well as the relevant ASME and API codes for the various machines and their ancillary units. Every so often, special agreement is made between the purchaser and the supplier, over and above these specifications, at the time of placing an order.
Machine test bed
The factor governing the design of the new test bed was the drive power to be provided and the nature of the drive. The drive power is rela-ted to the requirement of testing axial compressors by means of
suction-side throttling which, under normal suction conditions, absorb up to 50 MW power. The acutal drive power to be provided was reduced to only a third of the nomi-nal power, i.e. approx. 16 MW, by reducing the intake pressure through suction-side throttling to about a third of the atmospheric pressure. The type of the drive selected had to meet the requirement of performing the machine tests one by one, i.e. driving the MAN TURBO compres-sors with steam turbines manufactu-red by both MAN TURBOand other suppliers. In cases where the job-related driving unit is not available for driving high-power compressors during shop tests, a 16 MW conden-sing steam turbine of MAN TURBO make, integrated into the test bed, is used in the speed range of 3000 rpm to 5140 rpm. A thermal power plant, located nearby, sup-plies live steam (50 bar, 500 °C, 60 t/h) via a 1.6 km long pipeline. The steam turbine drive system further incorporates three special-purpose gearboxes capable of extending the speed range of the steam turbine from 1200 rpm to 7800 rpm, a condensing unit, steam pressure reducing and safety sys-tems, a complete oil supply unit (4000 l/min.) and a cooling tower plant having a capacity of 72 MW. In addition, two 2.5 MW electric motors (tandem power 5 MW), equipped with speed control and compatible gearboxes (output speeds of 600 rpm - 20800 rpm) are available for driving medium-power compressors.
Most of the preparatory work for turbomachinery testing is devoted
to the erection of interconnecting piping between the machine to be tested and the test-bed suction and measuring line system. Since the machines to be tested are of diffe-rent sizes, and have diffediffe-rent nozzle arrangements and machine connec-tions for media supply, the test bed set-up must offer the required flexi-bility to cope with each case. For this reason, the solution shown in Fig. 2 was selected. The machines to be tested are installed on two steel foundations of the same height but having different lengths. One foundation is 44 m long and has a free height of 4.25 m or 8.25 m. The levels marked ± 0.0 and - 4.0 in Fig. 2 are meant to accommodate ancillary units, such as for example oil supply units and coolers as shown in the foreground in Fig. 1. Smaller-sized machines are tested on the foundation, 22 m long, loca-ted alongside.
A foundation height of about 4 m has proved to be satisfactory for laying the interconnecting piping between the machines to be tested and the ventilation systemlocated below the concrete floor. Air suction ducts are embedded in the bay floor and covered with removable concre-te slabs. These air ducts are con-nected to the atmosphere via a sound-insulated suction chimney. Both the incoming air and extracted air systems are designed for air volumes of up to 250000 Nm3h.
Instrumentation and control system
The machine tests are controlled and supervised from a control room located atthe end of the bay. This control room incorporates a state-of-the-art electronic system for control-ling and regulating the machines to
be tested, the ancillary units and test bed peripheral equipment as well as for detecting, processing and evalu-ating the measuring values during the tests. It was thus possible to achieve considerable savings in terms of power and staff as compa-red to the former test beds.
A stored-programme controller (SPC, Fig.3) coodinates all the not time-critical controland regulation processes for the cooling-water and oil supply units as well as the indivi-dual units for the test bed motors and/or the steam turbine and for the machines and machine trains to be tested. All operations having a direct impact on the safety of the machi-nes to be tested are, as a rule,
processed and documented, all by computer control, via the measuring chain: sensor – signal cable – adap-ter cabinets – glass-fibre cable – computer network – screen – printer. In the adapter cabinets are located microprocessor-controlled measuring point selectors and high-resolution, low-interference digital voltmeters which are connected for data trans-fer to the superimposed computer network via glass-fibrecable. Transient functions can be monito-red, recorded and documented by means of a further measuring system using selected measuring points. This measuring system pro-cesses signal frequencies up to 10 Hz and is used in particular for determining the "surge limits" of compressors and for trend analysis of important variables.
Among the main activities during the mechanical test runs are measure-ments of vibrations and vibration analysis to demonstrate the mecha-nical characteristics of turbo and screw compressors as well as gas turbines. A measuring system is incorporated in the test bed for measuring and analyzing the shaft and casing vibrations of these machines; it is capable of detecting up to 64 measurement results and storing them for later analysis and documentation.
The levels of admissible shaft and casing vibrations during the test run are governed by the boundary limits specified in the relevant codes of practice or modifications as stipula-ted in the contracts signed between the purchaser and the manufacturer. performed by hand. These include
target value settings for speed adjustments, for steam temperatures and pressures, for oil pressures as well as the actuation of control and throttle valves and fittings.
A number of visual display units are available to evaluate at a glance the behaviour of the test bed peripheral equipment and the machines to be tested (Fig. 4).
All the measuring data is recorded and evaluated on-line with the help of a high-performance measuring value detection and processing system. The results of evaluation are displayed on the screen at about 1-second intervals making it very easy to operate, adjust and measure the different test points. The indivi-dual measuring values are detected,
Fig. 3: Stored programme controller Fig. 4: Control desks and visual display units
The data measured during the test run not only allow to judge the balanc-ing condition of the rotors, the loca-tion of their "critical speeds", the con-dition of the bearings and supports, but also serve as reference values for later operation in actual service. For demonstrating the guaranteed suction flow volumes, permanent metering pipes (DN 300 to DN 1000) are provided together with conver-ters and compatible orifices, with the help of which it is also possible to measure large suction flwo volumes of MAN TURBO axial compressors. The compressed atmospheric air is expanded behind the orifices via remote-controlled throttles and rele-ased into the atmosphere through a noise-insulated chimney. The mete-ring pipes are also used as part of closed circuits when
thermo-dyna-mic test runs have to be performed with gases other than air (e.g. N2,
CO2, He or gas mixtures) for
main-taining comparable thermo-dynamic conditions.
In the case of multi-casing turboma-chine sets, the scope of the periphe-ral measuring instruments such as temperature sensors, pressure transducers, vibration measuring instruments, shaft displacement proximitors, flow volume counters, etc. can extend up to 500 measu-ring points, the signals of which are scanned, processed and display/ documented virtually simultaneously. A computer-controlled calibration system servers for calibrating the individual transducers, sensors, etc. before and after each test.
• Supply air system with silencer,
filter and measuring section for determining the intake flow volume,
• Exhaust gas system with silencer
and chimney,
• Steel foundation with integrated
lube oil supply ofor accommoda ting the gas turbine to be tested,
• Starter unit with diesel engine,
hydraulic-clutch and gearbox,
• Feeding system for fluid and
gaseous fuels,
• Fluid friction dynamometer inclu
ding peripherals,
• Fire-fighting system, • Instrumentation and control
system for the gas turbine to be
Gas turbine test bench
The gas turbine test bench, located in the immediate vicinity of the com-pressor test bed, was commissioned in the year 1989. It consists of two units: one test stand for full-load testing of THM gas turbines and a testing area for gas turbine packa-ges including peripheral equipment and related compressors with power inputs of up to 25 MW.
Due to the high noise levels during the test, the THM gas turbines are housed in an enclosed test cell (Figs. 5 and 6). The cell is fitted with the following equipment.
The instrumentation and control system on this test bench is based on the same principles described above for the compressor test bed. However, a microprocessor is addi-tionally integrated into the gas turbi-ne test bench to control the fuel supply and gas turbine speeds as a function of the specified target values for the turbine speed and the load of the fluid friction dynamome-ter.
During the gas turbine testing, the main focus is on the demonstration of the ISO performance and thermal efficiency. Recording and processing
Thanks to the special-purpose test bed equipment, specifically tailored to suit gas turbines, it is possible to install, test and dismantle the gas turbines within a matter of a few days while the actual testing takes just a few hours.
Fig. 7 shows the test set-up of a package unit for an offshore plat-form, comprising a gas turbine with related compressors, set up on the package testing area (approx. 550 m2) of the gas turbine test bed.
This package unit consists of a THM 1304 gas turbine which drives a double-casing centrifugal compres-sor via a gear. The gas turbine also caters for the lube oil supply of the centrifugal compressors. A separate
buffer oil system including elevated tanks supplies buffer oil to the floa-ting ring seals of the compressors. According to the contract with the client, the shop tests for the machi-ne set comprising three packages had to include the following individu-al tests:
• No-load testing of the gas turbine, • Mechanical test rund of the entire
package unit, and
• Thermodynamic test run of the
centrifugal compressors.
Fig. 5: Gas turbine test bed,view of the THM-1304-10 gas turbine
Fig. 6: Gas turbine test bed,view of the fluid friction dynamometer
Prior to performing the above tests, the three gas turbines had already been subjected to mechanical and thermodynamic tests under full load and the compressors to mechanical test runs under vacuum conditions. During the thermodynamic test, the four stage groups of the double-casing centrifugal compressors were simultaneously tested with nitrogen in four closed circuits for maintaining comparable test conditions.
Coolers integrated into the test bed were available for setting up the clo-sed circuits. During the test runs, nitrogen was continuously fed into the circuits in order to replace the leakage amount into the atmosphere occurring via the buffer gas system.
system with an evaporator was used.
During the commissioning phase and the testing, the major compo-nents of the overall complex system, such as, for example,the buffer oil unit, were tested under the expected service conditions and adjusted accordingly. Subsequently, all the three package units were installed in the modules envisaged for the pur-pose on the dockyards of the plat-form manufacturer, and once again tested under nominal load conditions prior to shipment (Fig. 8).
FT8 gas turbine testing
In the package testing area of the gas turbine test bed, FT8 gas turbi-nes will also be tested in future
Fig. 7: Testing of a package unit for an offshore platform
Fig. 8: Module with integrated package unit for an offshore platform
tion was mainly focused on the question as to which machine should best absorb the gas turbine power. Out of the three possibilities explored - generator, fluid friction dynamometer, compressor - the compressor version was finally selected since it allows for maximum flexibility with regard to different speeds for testing the FT8 gas turbi-nes. Besides, an option had to be left open for power turbines having either right of left direction of rota-tion.
Fig. 9 shows a schematic represen-tation of the test bed set-up for testing FT8 gas turbines. The posi-tion of the gas turbines in the packa-ge testing area is determined by the connection of the exhaust gas nozz-le to the permanently instalnozz-led exhaust gas chimney. The periphe-rals of the gas turbines, comprising the air starter, fuel pump unit, lube oil supply and water injection system for NOxreduction, are arranged to
correspond to the actual configura-tion in later service. The gas turbine package itself is fitted with suction
speed. Based on past experience, the system selected is expected to afford a very stable control with closed circuits. This system is sche-duled for commissioning in spring 1992 for the first testing of an FT8-30 gas urbine under full load. silencer, air filter and package
venti-lation.
A precision dynamometer, located between the power turbine and a three-shaft special gearbox, is used for measuring the power turbine tor-ques. The gearbox steps up/down the output speeds of the gas turbi-nes to correspond to the speed range of 3870 rpm to 5400 rpm of a double-stage pipeline compressor designed for 25 MW drive power and operated in a closed circuit with nitrogen at pressures between 28 and 76 bar.
The heat of compression is first removed from the recycle gas in a closed-circuit cooler followed by a reduction of the built-up pressure to suction pressure by means of a throttle valve. Load variation on the compressor end is performed by fil-ling/emptying the closed circuit with nitrogen supplied by a suitable source. The gas turbine governor controls the fuel supply and the speed according to the target values specified for the power turbine
Fig. 9: Schematic of a closed circuit for full-load testing of FT8 gas turbines
MAN Turbomaschinen AG Steinbrinkstrasse 1 46145 Oberhausen / Germany Phone: +49. 208. 692-2385 Fax: +49. 208. 692-9786 [email protected] www.manturbo.com
In the interest of technical progress sub-ject to change without notice. Printed in germany. November 2002 TURBO ... ??????
