Gas Turbine Set Research Articles

The effect of dimple/protrusion arrangements on the comprehensive thermal performance of variable cross-section rotating channels for gas turbine blades

The cooling structure design of turbine blades plays a vital role in ensuring the safety and reliability of the entire gas turbine set. Our team's previous research revealed the influence of the rotating and variable cross-section effect on the aerothermal characteristics of the channel. In order to further enhance the cooling performance, four types of dimple/protrusion arrangement schemes are applied to five channels with different height ratios in this research. The detailed flow-heat transfer-friction characteristics and comprehensive thermal performance of each channel are obtained. The results show that the introduction of heat transfer enhancement element produces obvious heat transfer enhancement effect. Compared with the smooth reduced cross-section channel, the Nu/Nu0 is increased by 10.9 % (height ratio = 4:1, both of two passes are arranged by protrusions). For the rough expand cross-section channel, the Nu/Nu0 is increased by 8.9 % (height ratio = 1:2, the first pass is arranged by protrusions and the second pass is arranged by dimples). Within the scope of this paper, the arrangement scheme of both of two passes are arranged by dimples has the best comprehensive thermal performance. The arrangement scheme of both of two passes are arranged by protrusions has the highest Nu/Nu0, but also the highest f/f0.

Thermodynamic analysis of biomedical waste plasma gasification

Plasma gasification technology is one of the environmentally correct techniques that can be applied in the processing of biomedical waste (BW). This work aims to present thermodynamic studies with a simulation of the plasma gasification of BW produced in Brazil. Through thermodynamic analysis is determined the best operating point of the reactor, which corresponds to the temperature where the energy yield of syngas is maximum, and consequently the syngas chemical composition and its lower heating value (LHV). Finally, it is estimated the electrical power required in the BW processing and the potential for electricity generation through the burning of syngas in an internal combustion engine (ICE) and gas turbine set (GTS), and the capacity to supply the necessary energy in the plasma gasifier. As conclusion, the best operating point for the processing of typical Brazilian BW is at a temperature of 1040 K with a maximum gas energy yield of 2.25. For this temperature the syngas consists of 63.65 wt% of carbon monoxide and 5.35 wt% of hydrogen and LHV of 13.47 MJ/kg. Finally, for processing 1 kg/s of BW are required 6292 kW of electrical power, and the maximum electricity production potential is 3132 kW in ICE and 3758 kW in GTS.

Research of evaluation method of auxiliary frequency modulation in gas turbine unit

In this paper, according to the mechanical structure of the gas turbine set and the process of primary frequency modulation, the models including the speed regulating system, combustion chamber, temperature control system, torque control system, acceleration control system and synchronous generator are established. Bidirectional DC/DC converter and inverter model are established according to the circuit structure and corresponding control strategy. According to the primary frequency modulation process of the gas turbine, the control strategy of the energy storage system participating in the primary frequency modulation is set. The energy storage system uses the traditional droop control strategy and combines the primary frequency modulation process of gas turbine to improve the frequency modulation performance of gas turbine and offshore platform microgrid. Finally, PSCAD transient simulation software is used to build offshore platform and a multi-platform interconnection micro-grid model, results of the simulation show high performance of the designed microgrid.

Thermodynamic and economic analysis of a gas turbine set coupled with a turboexpander in a hierarchical gas-gas system

Investment per specific electric capacity of power plants and combined heat and power plants operating exclusively according to the Joule cycle (Simple Cycle Power Plants) is more than two times lower compared to combined gas-steam systems. This paper discusses a system comprising a turboexpander with a compressor and an air heater installed instead of a steam turbine. The results of thermodynamic calculations carried out for many alternatives gas turbine designs, including ones with and without heat regeneration and for hierarchical gas-gas system are analyzed. Using energy balances, the energy efficiency of various configurations of systems was calculated. In the presented economic calculations, aspects related to the ratio of the annual electricity production to the annual heat production play the role of important factors, as technology applied in combined heat and electricity generation, system energy efficiency, specific investment and sales price of the generated electricity determine the results. From the calculations we can see that the gas-gas system is more economically feasible than the gas-steam system in terms of heat production. With regard to electricity production, the gas-steam system is slightly more profitable than the gas-gas system. This advantage decreases along with the decrease in the gas price.

Development and exergetic assessment of a new hybrid vehicle incorporating gas turbine as powering option

In the current study, a novel hybridized system for vehicle applications is proposed, analyzed thermodynamically through energy and exergy approaches and evaluated through energy and exergy efficiencies. The current system comprises gas turbine set running on compressed natural gas (CNG), Li-ion battery, CNG tank, two generators, electric motor, power control unit (PCU), thermoelectric generator (TEG), organic Rankine cycle (ORC) and an absorption chiller system (ACS). The overall energy and exergy efficiencies of the proposed system are found to be 38% and 34% respectively at net output power of 63.6 kW from the turbine set. The maximum exergy destruction rate is found in the combustion chamber followed by the TEG unit. For a detailed analysis of the proposed system, a comprehensive parametric study is further carried out to detect the effect of varying the operating and ambient conditions on the system performance.

Methodology and Continuous Time Mathematical Model to Select Optimum Power of Gas Turbine Set for Dual-Fuel Gas-Steam Combined Heat and Power Plant in Parallel System

This paper contains the results of a study in which a novel approach using continuous time notation was applied in the search for the optimum capacity of a gas turbine designed for a dual-fuel gas-steam combined heat and power plant in a parallel system. As a result of the application of mathematical models of any functions that account for variations in time of all integrand quantities, for example prices of energy carriers, the model that was developed provides a way to analyze complex dependencies. The results of calculations obtained as a result of using this notation provide a rational selection of technologies and equipment designed for the energy industry. The results are based on an analysis involving a combined heat and power plant with an extraction-condensing steam turbine and extraction backpressure steam turbine for a wide range of the variability in energy prices and environmental charges corresponding to the current prices and environmental charges. All the curves were obtained using innovative methodology and mathematical model in which the total, discounted profit is calculated at the given moment and expressed as NPV achieved from the operation of dual-fuel gas-steam combined heat and power (CHP) plant.

Methodology and mathematical model with the continuous time for the selection of the optimal power of the gas turbine set for the dual fuel gas-steam combined cycle in a parallel system

Technological rationality with regard to the use of existing coal resources in power sector is based on the use of so-called clean coal technologies. One of them is the dual fuel gas-steam combined cycle technology, which couples the Joule gas turbine cycle with the Clausius-Rankine cycle of the steam turbine. Systems coupled in parallel of such units, apart from the construction of new power plants, has a large modernization potential for already existing combined heat and power plants and coal-fired power plants. Dual fuel systems may in fact be the result of a gas turbine repowering of the existing thermal coal structures. This paper presents technical and economic calculation results for various investment outlays, when the steam part works with supercritical and subcritical parameters of fresh steam, assuming different efficiency of the Clausius-Rankine cycle. Figures were obtained using innovative methodology and mathematical models of total NPV profit, discounted for the current moment achieved from the operation of the dual-fuel gas-steam power unit with a continuous time. Results are presented for a wide range of changes in prices of energy carriers and environmental charges, such as the CO2 emission allowances, including current prices level and fees.

Practical Dispute Resolution: A Case Study

This case study explores actions of an account manager of an important maintenance agreement and a field service engineer, both newly assigned to resolve reliability issues with a set of gas turbines and a deteriorated relationship with their client. The case walks the reader through a logical and practical methodology from collection of data to proposing corrective actions in engineering and account management. The case study provides discussions on gas turbine combustion technology, combustion air emissions, commissioning, and performance degradation as background for the exercise. A reading assignment is included for understanding. Answers to exercises are provided to check comprehension. The authors propose using this case study in university study, or in industry as an individual or group assignment.

Pump Hydro Storage and Gas Turbines Technologies Combined to Handle Wind Variability: Optimal Hydro Solution for an Italian Case Study

Load and wind energy profiles are totally uncorrelated, therein lies the problem of variable energy sources. Managing load with increasing wind penetration may call for operational ranges that conventional systems cannot readily access. Storage technologies could allow tolerating the unsteadiness of renewable sources with smaller fossil fuel plants capacity. Pumped Hydro Storage (PHS) is a crucial technology for balancing large steam power plants and may become increasingly important for storing renewable energies. Hence capacity ranges of PHS as well as its dynamic response to renewable power variability, will become progressively relevant. An integrated system made of a wind farm, a PHS plant and a set of gas turbines (GTs), as programmable fossil fuel devices, to handle renewable variability and maximize renewable energy exploitation, is studied in this paper. A specific case study is analyzed: a wind farm with a nameplate capacity equal to that installed in Sardinia is considered. To match the power output requested by the region with the integrated systems different configurations of PHS plant will be investigated. The impact of reversible or separate Francis machines with constant or variable speed will be analyzed in order to minimize electric power output overproduction and GTs fuel consumptions. Minimum and maximum capacity range for reversible or separate machines will be considered. The aim of the study is the optimum sizing and design of a PHS unit in a hybrid wind-hydro-gas turbine power plant to match the load request. Results in terms of PHS operation, water height behavior in upper and lower reservoirs, GT units power output, natural gas consumed and electric power output overproduction will be presented for each analyzed case.

Thermodynamic and economic comparative analysis of air and steam bottoming cycle

Article presents a comparative thermodynamic and economic analysis of air and steam bottoming cycle of a gas turbine. In order to make the comparison between air and steam bottoming cycle, identical gas turbines were selected. A decision was made to use gas turbine sets with a power output capacity included in the range of 5–25 MW. Considering that the air bottoming cycle agent is characterized by a low heat capacity, the systems under analysis have a better chance of competing with steam bottoming cycle configurations in the small power output capacity range. The gas turbines used in the calculations find application in commercial gas turbine steam bottoming cycles. Article includes results of the thermodynamic optimization of gas turbine air bottoming cycle. Calculations include design features of air bottoming cycle heat exchangers. The most essential aspect of the analysis is the economic comparison. The results are compared to performance characteristics of real gas turbine steam bottoming cycles. Quantities are determined that have a decisive impact on the considered units profitability and competitiveness compared to the popular technology based on steam bottoming cycle systems. The ultimate quantity that can be compared in the calculations is the marginal cost of electricity.

Feasibility analysis of a small-scale ORC energy recovery system for vehicular application

This paper analyses the feasibility of an “on-board” innovative and patented ORC recovery system. The vehicle thermal source can be either a typical diesel engine (1400cc) or a small gas turbine set (15–30kW). The sensible heat recovered from the exhaust gases feeds the energy recovery system that can produce sufficient extra power to sustain the conditioning system and other auxiliaries. The concept is suitable for all types of thermally propelled vehicles, but it is studied here for automotive applications. The characteristics of the organic cycle-based recovery system are discussed, and a preliminary design of the main components, such as the heat recovery exchanger, the evaporator and the pre-heater is presented. The main challenge are the imposed size and weight limitations that require a particular design for this compact recovery system. A possible system layout is analyzed and the requirements for a prototypal application are investigated.

The LETHE© (Low Emissions Turbo-Hybrid Engine) city car of the University of Roma 1: Final proposed configuration

A longstanding interest of the Authors' research group at University of Roma Sapienza (UDR1) is the design, development and fielding of a road prototype of a new concept of Hybrid Series vehicle, endowed with a small Gas Turbine set as a thermal engine. This solution offers several advantages with respect to traditional internal combustion engines and even to the existing generation of Hybrid propulsive systems: a reduced engine weight and size, lower emissions, substantially extended range, ease of maintenance, and more efficient braking energy recovery. In the LETHE© (Low Emissions Turbo-Hybrid Engine) the GT (gas turbine set) does not directly provide traction, but serves solely as a battery pack recharger. The vehicle is, in all respects, equivalent to a purely electric vehicle, except for the presence of an on-board recharger. Much care was placed in the design phase in the quest for an “optimal” design: first of all, an original method for identifying the most convenient degree of hybridization (ratio of the installed power of the battery pack to that of the GT) was defined and formalized, so that the resulting power balance between the two units satisfies the main design specifications and guarantees a practically acceptable operational life of the battery package while enabling the vehicle to complete a typical city mission (about 25–50 km) in a purely electric mode and without recharge. This paper presents a review of the previous conceptual and design results and describes in detail a possible road prototype configuration (weights, packaging of all units within the body of the vehicle, logic control unit, GT- and electric motor size and power, battery package characteristics). Some discussion is also devoted to the foreseeable impact of the deployment of a LETHE© fleet on the mid-range scenario of the Italian urban transportation system.

Testing of the Ultra-Micro Gas Turbine Devices (1 - 10 kW) for Portable Power Generation at University of Roma 1: First Tests Results

The ever increasing development of portable electronics has led to a higher demand for compact and reliable power sources. Significant resources are being presently dedicated to the study of micro machined gas turbines, because of their remarkable power density. The paper reports the procedures and the results of a series of tests conducted at the Department of Mechanical & Aerospace Engineering of University of Roma 1, to obtain the map of an ultra-micro gas turbine device, and the head losses and the combustion efficiency of the corresponding ultra-micro combustion chamber, fed by a mixture of butane and propane. This work is a part of a research aimed at the conception, design and prototyping of an ultra-micro thermo-electrical device for portable power generation. The novelty of the research consists in the fact that the thermal engine is a (ultra-micro) gas turbine set. In a subsequent stage, several different configurations have been assessed to select the most proper geometry and structural characteristics of the most relevant components (radial compressor, radial turbine, combustion chamber, electric motor and generator, bearings, regenerative heat exchanger).

A Study on Semi-Physical Simulation for Marine Gas Turbine Generator Set Based on Hardware Agent

The simulation research on gas turbine generator set has the important practical significance for its main development direction in marine power plant. The research object is semi-physical simulation for marine gas turbine generator set. This paper presents a new type of semi-physical simulation scheme based on “hardware agent” through reviewing the existing the structure characteristics and deficiency of semi-physical simulation system of gas turbine device. The theoretical basis and operation control strategy and framework of the new project were discussed. The experiments on sudden load-up and load rejection were made based on new type of semi-physical simulation system for marine gas turbine set and had a good test effect.

The Application of Mechanical Failure Diagnosis Expert System for the Improvement of Vibration Fault Monitor and Diagnosis Based on Rough Set Theory

Focuses on rough set theory and the genetic algorithms and theories on their integration mechanism based on the study of the failure diagnosis on gas turbine-set, A new algorithm were put forward in the discretization of continuous attribute, attribute reduction and value reduction methods based on the classical set theory and rough set theory and solved the difficult problem which expert system to obtain the rules in the paper. Knowledge system attribute table is regard as a major tool to reduce the rules of expert system in which unnecessary attributes are eliminated. The redundancy of failure diagnosis information and the complexity of structure in failure diagnosis expert system are revealed. It brings forth the reliable and practical method, which have further enriched and improved the theories on the vibration fault monitor and diagnosis of a large gas turbine-set by testing and verifying

Highly Efficient IGFC Hybrid Power Systems Employing Bottoming Organic Rankine Cycles With Optional Carbon Capture

This study examines the performance of a solid oxide fuel cell- (SOFC-) based integrated gasification power plant concept at the utility scale (>100 MW). The primary system concept evaluated was a pressurized ∼150 MW SOFC hybrid power system integrated with an entrained-flow, dry-fed, oxygen-blown, slagging coal gasifier and a combined cycle in the form of a gas turbine and an organic Rankine cycle (ORC) power generator. The analyzed concepts include carbon capture via oxy-combustion followed by water knockout and gas compression to pipeline-ready CO2 sequestration conditions. The results of the study indicate that hybrid SOFC systems could achieve electric efficiencies approaching 66% [lower heating value (LHV)] when operating fueled by coal-derived clean syngas and without carbon dioxide capture. The system concept integrates SOFCs with the low-pressure turbine spool of a 50 MW Pratt & Whitney FT8-3 TwinPak gas turbine set and a scaled-up, water-cooled 20 MW version of the Pratt & Whitney (P&W) PureCycle ORC product line (approximately 260 kW). It was also found that a system efficiency performance of about 48% (LHV) is obtained when the system includes entrained-flow gasifier and carbon capture using oxygen combustion. In order to integrate the P&W FT8 into the SOFC system, the high-pressure turbine spool is removed which substantially lowers the FT8 capital cost and increases the expected life of the gas turbine engine. The impact of integrating an ORC bottoming cycle was found to be significant and can add as much as 8 percentage points of efficiency to the system. For sake of comparison, the performance of a higher temperature P&W ORC power system was also investigated. Use of a steam power cycle, in lieu of an ORC, could increase net plant efficiency by another 4%, however, operating costs are potentially much lower with ORCs than steam power cycles. Additionally, the use of cathode gas recycle is strongly relevant to efficiency performance when integrating with bottoming cycles. A parameter sensitivity analysis of the system revealed that SOFC power density is strongly influenced by design cell voltage, fuel utilization, and amount of anode recycle. To maximize the power output of the modified FT8, SOFC fuel utilization should be lower than 70%. Cathode side design parameters, such as pressure drop and temperature rise were observed to only mildly affect efficiency and power density.

The Turbine Machine Fault Prediction Based on Kernel Principal Component Analysis

Kernel principal component analysis (KPCA) is presented and is applied to predict the huge electro-mechanical system fault. Take the gas turbine set of Beijing Yanshan Petrochemical Refinery as the research object. KPCA uses the historical normal data of vibration intensity value to establish a prediction system. And then it is used to forecast the collected data for judging whether the turbine set is in normal. The simulation experiment result indicates the effectiveness of the method and the running state can be judged as normal or not from the result. And the experiment also shows KPCA can obtain a satisfactory prediction result.

A Proposal for CO2 Abatement in Urban Areas: The UDR1–Lethe© Turbo-Hybrid Vehicle

For years the interest of the University of Roma 1 (UDR1) research group has been focused on the development of a Hybrid Series vehicle (called Lethe©), different from standard ones, thanks to the use of a Gas Turbine (GT) set as a thermal engine. The reason for this choice resides in the opportunity to reduce weight and dimensions, in comparison to a traditional Internal Combustion Engine. It’s currently not possible to use the GT engine set directly for the vehicle traction, so the UDR1 HS configuration only shows the GT set connected with the electric generator. The result is that the traction is purely electric. The resulting engine configuration is commonly described as a Hybrid Series Plug In. Several previous studies have been carried out, and this research has allowed us to define the correct ratio (Degree of Hybridization) between the installed power of the battery pack and that of the GT electric generator which simultaneously guarantee the main life for the battery package and the capacity of the vehicle to complete a common mission without lack of energy or stopping. This article reports the final step of the research: once all data has been calculated, how to “hybridize” a commercial city car, passenger sedan or any other vehicle.

Optimization of Distributed Trigeneration Systems Integrated with Heating and Cooling Micro-grids

ABSTRACT The article deals with the influence of the amortization period in the optimization of a distributed urban district heating and cooling trigeneration system. The model, presented in detail in [1], is based on a Mixed Integer Linear Program (MILP) and includes a set of micro-cogeneration gas turbines for producing electricity and thermal energy and a set of absorption chillers, driven by cogenerated heat, for producing cooling energy. Micro-gas turbines and absorption chillers can be used instead of purchasing electricity from the grid, producing thermal energy by boilers and cooling energy by compression chillers. Moreover, various building can be connected each other through a district heating and cooling network (DHC network). The optimization specifies the kind, the number and the location of cogeneration equipment and absorption machines, the size and the position of district heating and cooling pipelines as well as the optimal operation of each component. The objective function takes into ac...

Lethe<sup>@</sup>-Udr1 Passenger Sedan Final Proposed Configuration

For years the interest of the UDR1 researcher group has been focused on the development of a Hybrid Series (HS) vehicle, different from the standard one, using a Gas Turbine (GT) set as a thermal engine. The reason of this choice resides in the opportunity to reduce weight and dimension, in comparison to a traditional In- ternal Combustion Engine (ICE). It’s not possible to use the GT engine directly for the vehicle traction, so the UDR1 HS configuration shows the GT set connected with the electric generator only. The result is that the traction is pure electric. Many efforts are spent in the definition of a generic scientific method to define the correct ratio HD (the Hybridization Degree) between the installed power of the battery pack and that of the GT electric generator which simultaneously guarantee the main life for the battery package and the ca- pacity of the vehicle to complete a common mission (about 15 km - 30 km) without lack of energy or stop. This paper reports all studies carried out and finally proposes a possible configuration (weight distribution, VMU logic control, GT dimensions and power rate, battery package characteristics and so on) for mid term solution in the Italian transport system.