scholarly journals Simulation and Flow Analysis of the Hole Diaphragm Labyrinth Seal at Several Whirl Frequencies

Energies ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 379
Author(s):  
Xiang Zhang ◽  
Yinghou Jiao ◽  
Xiuquan Qu ◽  
Guanghe Huo ◽  
Zhiqian Zhao
Keyword(s):  
Gas Turbine ◽  
Reverse Flow ◽  
Fluid Dynamic ◽  
Dynamic Performance ◽  
Flow Analysis ◽  
Labyrinth Seal ◽  
Unusual Phenomenon ◽  
Complex Fluid ◽  
Turbine Design ◽  
Velocity Turbulence

The seal is designed to reduce leakage and improve the efficiency of gas turbine machines, and is an important technology that needs to be studied in gas turbine design. A series of seals were proposed to try to achieve this goal. However, due to the complex fluid dynamic performance of the seal-rotor system, the seal structure can obtain both the best leakage performance and best rotordynamic performance. This paper presents a detailed flow analysis of the hole diaphragm labyrinth seal (HDLS) at several whirl frequencies and several rotation speeds. The pressure drop, velocity, turbulence kinetic energy and leakage performance of the HDLS were discussed by simulations. An interesting exponential–type relationship between rotation speeds and leakage flow at different whirl frequencies was observed by curve fitting technology. A reverse flow rate was proposed to describe such an unusual phenomenon. Such a relationship can be used to further establish the leakage model of the HDLS and other similar seals.

scholarly journals Investigating of Turbine Blades Geometrical Change Effects on Dynamic Performance of IGT-25 Gas Turbine

2019 ◽  
Author(s):  
Nima Zamani Meymian ◽  
Hossein Rabiei
Keyword(s):  
Gas Turbine ◽  
Mass Flow ◽  
Gas Flow ◽  
Fluid Dynamic ◽  
Dynamic Performance ◽  
Turbine Blades ◽  
Gas Generator ◽  
Air Compressor ◽  
Power Turbine ◽  
Geometrical Change

In the paper, the effect of gas generator turbine blades’ geometrical change has been studied on the overall performance of a twin-shaft 25MW gas turbine with industrial application, under dynamic conditions. Geometrical changes include change of thickness and height of gas generator turbine blades which in turn would result in the change in the mass flow rate of passing hot gas, as well as isentropic efficiency in each stage of the turbine. Gas turbine modeling in the paper is zero-dimensional and takes place with consideration of dynamic effects of volume on air compressor components, combustion chamber, gas generator turbine, power turbine, fuel system, as well as effects of heat transfer dynamics between blades, gas path, and effects of operators on inlet guide vanes, fuel valves, and air compressor discharge valve. In the mathematical model of each of the components, steady-state characteristics curves have been used, extracted from 3-Dimensional computational fluid dynamics (CFD). To do so, characteristic curves of the first and second stages of the four-stage turbine have been updated through 3-D fluid dynamic analysis so that the effect of geometrical changes in turbine blades would be applied. Results from effects of these changes on characteristics of transient gas flow including output power of gas generator turbine and power turbine, inlet and outlet temperatures of turbine stages, as well as air and fuel mass flow rates have been provided from the start-ups until reaching the nominal load would be achieved.

Probabilistic Thermal Analysis of Gas Turbine Internal Hardware

2006 ◽  
Author(s):  
Ethan Stearns ◽  
Dave Cloud ◽  
Tom Filburn
Keyword(s):  
Thermal Analysis ◽  
Gas Turbine ◽  
Mass Flow ◽  
Thermal Analyses ◽  
Flow Analysis ◽  
Engine Performance ◽  
Labyrinth Seal ◽  
Metal Temperature ◽  
Initial Development ◽  
Probabilistic Flow

This paper documents the initial development of a method to perform probabilistic thermal analyses of gas turbine internal hardware and uses the turbine interstage seal of a turbofan engine as an example. The purpose of this analysis is to investigate the variability in steady state metal temperature due to variability in the secondary flow system. In addition to quantifying the variability in metal temperature, the sensitivity of the temperature to individual input variables is determined. As a prerequisite for a probabilistic thermal analysis, a probabilistic flow analysis was executed, with variability in engine performance and hardware geometry yielding variability in mass flow rates, heat generation and local swirl velocity. These outputs were used as stochastic inputs for the probabilistic thermal analysis. The analysis was run with correlated input as well as independently varying inputs. The results of this analysis showed that the metal temperature at the tip of the seal was sensitive and highly correlated to air source temperature, as expected. The mass flow rate of air across the seal and heat transfer coefficient also affected the metal temperature. By using correlated input variability, it is shown that variability in metal temperature is ultimately caused by variability in labyrinth seal clearance.

GASCAN—An Interactive Code for Thermal Analysis of Gas Turbine Systems

1988 ◽  
Vol 110 (2) ◽  
pp. 201-209 ◽  
Author(s):  
M. A. El-Masri
Keyword(s):  
Gas Turbine ◽  
System Analysis ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
System Optimization ◽  
Interactive System ◽  
Turbine Cooling ◽  
Balance Analysis ◽  
Three Dimensional Models ◽  
Turbine Design

A general, dimensionless formulation of the thermodynamic, heat transfer, and fluid-dynamic processes in a cooled gas turbine is used to construct a compact, flexible, interactive system-analysis program. A variety of multishaft systems using surface or evaporative intercoolers, surface recuperators, or rotary regenerators, and incorporating gas turbine reheat combustors, can be analyzed. Different types of turbine cooling methods at various levels of technology parameters, including thermal barrier coatings, may be represented. The system configuration is flexible, allowing the number of turbine stages, shaft/spool arrangement, number and selection of coolant bleed points, and coolant routing scheme to be varied at will. Interactive iterations between system thermodynamic performance and simplified quasi-three-dimensional models of the turbine stages allow exploration of realistic turbine-design opportunities within the system/thermodynamic parameter space. The code performs exergy-balance analysis to break down and trace system inefficiencies to their source components and source processes within the components, thereby providing insight into the interactions between the components and the system optimization tradeoffs.

An Innovative Inlet Air Cooling System for IGCC Power Augmentation: Part III — Computational Fluid Dynamic Analysis of Syngas Combustion in Nitrogen-Enriched Air

2013 ◽  
Author(s):  
Mirko Morini ◽  
Michele Pinelli ◽  
Pier Ruggero Spina ◽  
Anna Vaccari
Keyword(s):  
Gas Turbine ◽  
Liquid Nitrogen ◽  
Cooling System ◽  
Reverse Flow ◽  
Fluid Dynamic ◽  
Molar Fraction ◽  
Pollutant Emissions ◽  
Air Cooling ◽  
Inlet Section ◽  
Turbine Inlet

In recent years, an innovative system for power augmentation has been presented by the authors. The system is based on gas turbine inlet air cooling by means of liquid nitrogen sprayers. This system is not characterized by the limits of water evaporative cooling (i.e. lower temperature limited by air saturation) and refrigeration cooling (i.e. effectiveness limited by pressure drop in the heat exchangers), but the injection of a large amount of liquid nitrogen at gas turbine inlet section can be disputable. In fact, the air composition changes, though not considerably, after nitrogen injection. The oxygen content always seems high enough to allow a regular combustion. In any case, local effects should be further investigated. In this paper, the effect of the increase in nitrogen molar fraction of combustion air is evaluated. A micro gas turbine combustion chamber geometry (i.e. a reverse flow tubular combustor) is taken into consideration since its model has been widely validated by the authors. The analyses are performed by considering two different fuels: methane (which is the design fuel) and syngas. The results are compared in terms of overall performance (e.g. TIT, pollutant emissions) and local distributions (e.g. flow fields, flame shape and position).

scholarly journals Experimental Investigation and Comparison of the Thermal Performance of Additively and Conventionally Manufactured Heat Exchangers

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 574
Author(s):  
Ana Vafadar ◽  
Ferdinando Guzzomi ◽  
Kevin Hayward
Keyword(s):  
Surface Roughness ◽  
Thermal Performance ◽  
Heat Exchangers ◽  
High Efficiency ◽  
Cooling System ◽  
Fluid Dynamic ◽  
Dynamic Performance ◽  
Experimental Studies ◽  
Manufacturing Method ◽  
Industrial Sectors

Air heat exchangers (HXs) are applicable in many industrial sectors because they offer a simple, reliable, and cost-effective cooling system. Additive manufacturing (AM) systems have significant potential in the construction of high-efficiency, lightweight HXs; however, HXs still mainly rely on conventional manufacturing (CM) systems such as milling, and brazing. This is due to the fact that little is known regarding the effects of AM on the performance of AM fabricated HXs. In this research, three air HXs comprising of a single fin fabricated from stainless steel 316 L using AM and CM methods—i.e., the HXs were fabricated by both direct metal printing and milling. To evaluate the fabricated HXs, microstructure images of the HXs were investigated, and the surface roughness of the samples was measured. Furthermore, an experimental test rig was designed and manufactured to conduct the experimental studies, and the thermal performance was investigated using four characteristics: heat transfer coefficient, Nusselt number, thermal fluid dynamic performance, and friction factor. The results showed that the manufacturing method has a considerable effect on the HX thermal performance. Furthermore, the surface roughness and distribution, and quantity of internal voids, which might be created during and after the printing process, affect the performance of HXs.

scholarly journals Feasibility of a Helium Closed-Cycle Gas Turbine for UAV Propulsion

2020 ◽  
Vol 11 (1) ◽  
pp. 28
Author(s):  
Emmanuel O. Osigwe ◽  
Arnold Gad-Briggs ◽  
Theoklis Nikolaidis
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Low Noise ◽  
Closed Cycle ◽  
Propulsion Systems ◽  
Component Design ◽  
Readiness Level ◽  
Aerial Vehicle ◽  
Turbine Design

When selecting a design for an unmanned aerial vehicle, the choice of the propulsion system is vital in terms of mission requirements, sustainability, usability, noise, controllability, reliability and technology readiness level (TRL). This study analyses the various propulsion systems used in unmanned aerial vehicles (UAVs), paying particular focus on the closed-cycle propulsion systems. The study also investigates the feasibility of using helium closed-cycle gas turbines for UAV propulsion, highlighting the merits and demerits of helium closed-cycle gas turbines. Some of the advantages mentioned include high payload, low noise and high altitude mission ability; while the major drawbacks include a heat sink, nuclear hazard radiation and the shield weight. A preliminary assessment of the cycle showed that a pressure ratio of 4, turbine entry temperature (TET) of 800 °C and mass flow of 50 kg/s could be used to achieve a lightweight helium closed-cycle gas turbine design for UAV mission considering component design constraints.

Gas Turbine Recuperator Technology Advancements

1972 ◽  
Author(s):  
C. F. McDonald
Keyword(s):  
Heat Exchanger ◽  
Power Systems ◽  
Gas Turbine ◽  
Substantial Reduction ◽  
Liquid Fuels ◽  
Cycle Space ◽  
Fuel Savings ◽  
Efficient Heat Transfer ◽  
The Cost ◽  
Turbine Design

Because of intense development in the aircraft gas turbine field over the last 30 years, the fixed boundary recuperator has received much less development attention than the turbomachinery, and is still proving to be the nemesis of the small gas turbine design engineer. For operation on cheap fuel, such as natural gas, the simple cycle-engine is the obvious choice, but where more expensive liquid fuels are to be burned, the economics of gas turbine operation can be substantially improved by incorporating an efficient, reliable recuperator. For many industrial, vehicular, marine, and utility applications it can be shown that the gas turbine is a more attractive prime mover than either the diesel engine or steam turbine. For some military applications the fuel logistics situation shows the recuperative gas turbine to be the most effective power plant. For small nuclear Brayton cycle space power systems the recuperator is an essential component for high overall plant efficiency, and hence reduced thermal rejection to the environment. Data are presented to show that utilization of compact efficient heat transfer surfaces developed primarily for aerospace heat exchangers, can result in a substantial reduction in weight and volume, for industrial, vehicular, marine, and nuclear gas turbine recuperators. With the increase in overall efficiency of the recuperative cycle (depending on the level of thermal effectiveness, and the size and type of plant), the cost of the heat exchanger can often be paid for in fuel savings, after only a few hundred hours of operation. Heat exchanger surface geometries and fabrication techniques, together with specific recuperator sizes for different applications, are presented. Design, performance, structural, manufacturing, and economic aspects of compact heat exchanger technology, as applied to the gas turbine, are discussed in detail, together with projected future trends in this field.

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