Preventative Metallurgical Failure Evaluation of Free Power Turbine Nozzle of Aero-Derivative Gas Turbine Engine

2019 ◽  
Vol 19 (6) ◽  
pp. 1537-1543
Author(s):  
Sulaiman A. Al-Baltan ◽  
Alaaeldin H. Mustafa ◽  
Shouwen Shen
Author(s):  
W Cheng ◽  
D. G. Wilson ◽  
A. C. Pfahnl

The performance and emissions of two alternative types of gas turbine engine for a chosen family vehicle are compared. One engine is a regenerative 71 kW gas turbine; the other is a hybrid power plant composed of a 15 kW gas turbine and a 7 MJ flywheel. These engines would give generally similar vehicle performance to that produced by 71 kW spark ignition and compression ignition engines. (The turbine engines would be lighter and, with a free power turbine, would have a more favourable torque-speed curve (1), giving them some advantages.) Results predict that for long-distance trips the hybrid engine would have a considerably better fuel economy and would produce lower emissions than the piston engines, and that the ‘straight’ gas turbine would be even better. For shorter commuting trips the hybrid would be able to run entirely from energy acquired and stored from house electricity, and it could therefore be the preferred choice for automobiles used primarily for urban driving when environmental factors are taken into account. However, the degradation of remaining energy in flywheel batteries and thermal energy in the regenerator and other engine hot parts between use periods will result in more energy being used than for the straight gas turbine engine using normal liquid fuel. The higher initial cost and greater complexity of the hybrid engine will be additional disadvantages.


Author(s):  
Stephen A. Long ◽  
Patrick A. Reiger ◽  
Michael W. Elliott ◽  
Stephen L. Edney ◽  
Frank Knabe ◽  
...  

For the purpose of assessing combustion effects in a small gas turbine engine, there was a requirement to evaluate the rotating temperature and dynamic characteristics of the power turbine rotor module. This assessment required measurements be taken within the engine, during operation up to maximum power, using rotor mounted thermocouples and strain gages. The acquisition of this data necessitated the use of a telemetry system that could be integrated into the existing engine architecture without affecting performance. Due to space constraints, housing of the telemetry module was limited to placement in a hot section. In order to tolerate the high temperature environment, a cooling system was developed as part of the integration effort to maintain telemetry module temperatures within the limit allowed by the electronics. Finite element thermal analysis was used to guide the design of the cooling system. This was to ensure that sufficient airflow was introduced and appropriately distributed to cool the telemetry cavity, and hence electronics, without affecting the performance of the engine. Presented herein is a discussion of the telemetry system, instrumentation design philosophy, cooling system design and verification, and sample of the results acquired through successful execution of the full engine test program.


2020 ◽  
Vol 178 ◽  
pp. 01038
Author(s):  
George Marin ◽  
Dmitrii Mendeleev ◽  
Boris Osipov ◽  
Azat Akhmetshin

Modern energy development strategies of advanced countries are based on the construction of gas turbine units which is associated with sufficiently high values of thermal efficiency and a relatively short term for putting them into operation. In this paper, the NK-8 engine is considered. It is modernized with a mixing chamber and a power turbine for the purpose of its ground application. A study was conducted of the injection of an additional working fluid into the flow part of a dual-circuit gas turbine engine. Steam is used as an injectable substance. For research a mathematical model was created in the AS «GRET» software package. The studies were carried out under constant load, the maximum load during injection was determined. An additional worker can be supplied with summer power limitations when it is necessary to increase the power of a gas turbine installation. Studies have shown that the maximum power that can be obtained by supplying steam to the flow part is 32.2 MW.


Author(s):  
Karl F. Prigge ◽  
Jerry W. Watts ◽  
Terrence E. Dwan

A multi-input, multi-output (MIMO) controller for an advanced gas turbine has been developed and tested using a computer simulation. The engine modeled is a two-and-one half spool gas turbine with both an intercooler and a regenerator. In addition, variable stator vanes are present in the free-power turbine. This advanced engine is proposed for future naval propulsion for both mechanical drive ships and electrical drive ships. The designed controller controls free-power turbine speed and turbine inlet temperature using fuel flow and angle of the stator vanes. The controller will also have four modes of operation to deal with over temperature and over speed conditions. An eight state reduced order controller was used with pole placement and LQR to arrive at control gains. Both these methods required considerable insight into the problem. This insight was provided by previous experience with controller design for a less complicated engine, and also by use of a polyhedral search model of the gas turbine engine. The difficulty with a MIMO controller was that both inputs affect both of the control variables. The classical resolution of this problem is to have one input control one variable at a fast time constant and the other input control the other variable at a slow time constant. The “optimal” resolution of this problem is analyzed using the transient curves and basic control theory.


Author(s):  
A. Yu. Brycheva ◽  
V. D. Molyakov

The article considers capabilities of the gas turbine engine to be used as a drive of the crude oil pump. It is noted that the gas turbine drive proves to be more advantageous than the electric motor when there is no external power supply or building periods of power transmission lines are significantly long, as well as quantities of oil products pumped are often changed.The main objective of this work is to select the optimum engine cycle parameters for a particular pump model, which oil pumping stations use. As an object of research, a crude oil pump of the НМ 10000 / 1.25-210 brand was chosen. The paper presents technical characteristics of the HM 10000 / 1.25-210 centrifugal pump and experimental values of head, power, and efficiency of the pump for a number of feeds. To obtain the pressure and power characteristics of a centrifugal pump for different rotational speeds of the rotor the similarity formulas are used.As the centrifugal pump drive, the paper considers a two-shaft plant with the free power turbine. This scheme was chosen in accordance with the features of the gas turbine pump unit at the oil pumping station. It is noted that the free power turbine scheme allows us to bring into accordance the characteristics of a gas turbine engine and an oil pump in abnormal modes, since there is no mechanical connection between high and low pressure turbines.The paper presents the calculated parameters of the gas turbine engine cycle with power Ne = 8 MW. The graphs show dependence of the airflow rate GB, the specific fuel consumption Ce and the efficiency ηe on the degree of pressure increase πk in the compressor. In accordance with the graphs, the optimum value of the degree of pressure increase πk = 15 in the compressor  is adopted. With πk = 15, the specific fuel consumption in the gas turbine engine with power Ne = 8 MW is equal to Ce = 0,22 kg/kW*h and the airflow rate is GB = 20,5kg/s. The efficiency of the engine with the selected parameters is ηe = 38,4%.It is noted that in order to ensure the most economical gas turbine engine operation, it is necessary to select the optimal control program, which is determined taking into account the load characteristics, in this case the characteristics of the pump.


Author(s):  
Stephen A Long ◽  
Stephen L Edney ◽  
Patrick A Reiger ◽  
Michael W Elliott ◽  
Frank Knabe ◽  
...  

For the purpose of assessing combustion effects in a small gas turbine engine, there was a requirement to evaluate the rotating temperature and dynamic characteristics of the power turbine rotor module. This assessment required measurements be taken within the engine, during operation up to maximum power, using rotor mounted thermocouples and strain gauges. The acquisition of this data necessitated the use of a telemetry system that could be integrated into the existing engine architecture without affecting performance. As a result of space constraints, housing of the telemetry module was limited to placement in a hot section. To tolerate the high temperature environment, a cooling system was developed as part of the integration effort to maintain telemetry module temperatures within the limit allowed by the electronics. Finite element thermal analysis was used to guide the design of the cooling system. This was to ensure that sufficient airflow was introduced and appropriately distributed to cool the telemetry cavity, and hence electronics, without affecting the performance of the engine. Presented herein is a discussion of the telemetry system, instrumentation design philosophy, cooling system design and verification, and sample of the results acquired through successful execution of the full engine test program.


Author(s):  
Xueyou Wen ◽  
Xiying Niu ◽  
Yonglai Li ◽  
Shunwang Yu ◽  
Feng Lin ◽  
...  

Abstract In order to verify that a high-power marine gas turbine engine can be redesigned to be a reversible one, concept verification was done on a reversible turbine test rig. The reversible power turbine test pieces were designed, which are transformed to be capable of rotating reversely. And more than 100 times of operational tests were done for the switching devices. Based on the reversible turbine test rig, 50 times of switching tests between normal and reverse rotational direction were done by compressed air under low temperature condition. While more than 100 times of operational tests were done with hot gas at temperature of 400–500 °C. The tests results show that the switching devices could operate flexibly and the output power reached over 40% of rated power condition. During the switching tests between the normal and reverse rotational direction, the propeller could stop running. All of these verify the concept feasibility of reversible gas turbine engine. Based on this concept, preliminary design was completed for a high-power marine gas turbine engine redesigned into a reverse one, which laid solid foundation for the following detailed design, experimental verification and application.


Author(s):  
Xiying Niu ◽  
Feng Lin ◽  
Weishun Li ◽  
Chen Liang ◽  
Shunwang Yu ◽  
...  

Gas turbine engines are widely used as the marine main power system. However, they can’t reverse like diesel engine. If the reversal is realized, other ways must be adopted, for example, controllable pitch propeller (CPP) and reversible gearing. Although CPP has widespread use, the actuator installation inside the hub of the propeller lead to the decrease in efficiency, and it takes one minute to switch “full speed ahead” to “full speed astern”. In addition, some devices need to be added for the reversible gearing, and it takes five minutes to switch from “full speed ahead” “to “full speed astern”. Based on the gas turbine engine itself, a reversible gas turbine engine is proposed, which can rotate positively or reversely. Most important of all, reversible gas turbine engine can realize operating states of “full speed ahead”, “full speed astern“ and “stop propeller”. And, it just takes half of one minute to switch “full speed ahead” to “full speed astern”. Since reversible gas turbine engines have compensating advantages, and especially in recent years computational fluid dynamics (CFD) technology and turbine gas-dynamics design level develop rapidly, reversible gas turbine engines will be a good direction for ship astern. In this paper, the power turbine of a marine gas turbine engine was redesigned by three dimensional shape modification, and the flow field is analyzed using CFD, in order to redesign into a reverse turbine. The last stage vanes and blades of this power turbine were changed to double-layer structure. That is, the outer one is reversible turbine, while the inner is the ahead one. Note that their rotational directions are opposite. In order to realize switching between rotation ahead and rotation astern, switching devices were designed, which locate in the duct between the low pressure turbine and power turbine. Moreover, In order to reduce the blade windage loss caused by the reversible turbine during working ahead, baffle plates were used before and after the reversible rotor blades. This paper mainly studied how to increase the efficiency of the reversible turbine stage, the torque change under different operating conditions, rotational speed and rotational directions, and flow field under typical operating conditions. A perfect profile is expected to provide for reversible power turbine, and it can decrease the blade windage loss, and increase the efficiency of the whole gas turbine engine. Overall, the efficiency of the newly designed reversible turbine is up to 85.7%, and the output power is more than 10 MW, which can meet requirements of no less than 30% power of rated condition. Most importantly, the shaft is not over torque under all ahead and astern conditions. Detailed results about these are presented and discussed in the paper.


Author(s):  
V. Matviienko ◽  
V. Ocheretianyi

High energetic efficiency of cogenerative gas-turbine engine (GTE) is due to by deep utilization of exhaust gases heat and greater portion of produced electrical energy, with is achieved by complication of Brayton cycle application of overexpansion in turbine. Such method is realized in GTE with turbo-compressor utilizer (TCU) attached to exhaust of the engine. TCU consists of the overexpansion turbine, exhaust compressor and gas cooler between them. Gas cooler in TCU is used as a water boiler-utilizer. This paper presents characteristics of GTE with TCU in variable regimes of loading. It is found, that GTE with TCU at nominal and partial loadings has higher efficiency, than simple cycle GTE. Construction of GTE with TCU can be performed with free TCU and blocked TCU, which is mechanically linked to power turbine. High energy efficiency of GTE with free TCU is proved, enabling to maintain overall efficiency on high level on decrease of electrical power. It is suggested that GTE with free TCU is more efficient for energy supply of municipal objects, and its constructive scheme provides stable delivery of heat energy to consumer upon significant variation of electric loading.


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