PROJECT: STUDY OF A CAN ANNULAR COMBUSTION CHAMBER AND TO INCREASE ITS EFFICIENCY WITH A NOVEL SWIRL DESIGN DEPARTMENT OF AERONAUTICAL ENGINEERING GUIDE: ASSISTANT PROF. MS.IRISH ANGELIN MEMBERS: J.SUMENDRAN J. LIVING GODSON S.DEEPAK KUMAR

ABSTRACT The purpose of the project is to develop a swirl design which will help in the production of turbulence inside the primary zone of the combustion chamber. This turbulence enhances the mixing of fuel and air. The essential mixture of fuel and air helps in reducing the percentage of unburned gas and therefore, the efficiency of the combustion can be increased. The swirl designed for the can-annular combustor is to be evaluated using computational fluid dynamics and the optimization of the design is to be done.

OBJECTIVES To design a can-annular combustion chamber To design a novel swirl for the combustor To increase the efficiency of the combustor SCOPE Optimization of the design of the combustor Design an innovative swirl To improve the performance of the combustor

PROBLEM STATEMENT Without the use of the swirl design in the snout area of the combustor, some of the gas remains unburnt in the combustor. To burn all the gas in the combustor, a high level of turbulence is to created and it can be achieved through the swirl. The various swirl design to be designed: 1.Swirl with 30 ̊̊ 2.Swirl with 45 ̊ 3.Swirl with 60 ̊ These swirl designs are to be analyzed using CFD and the best optimum design for the project is to be chosen.

IDEAL BRAYTON CYCLE FOR TURBOJET ENGINE P-v diagramT-s diagram

CAN ANNULAR COMBUSTOR MAIN COMPONENTS 1. Combustion Wrapper 2.Combustion Can Cover 3.Fuel Nozzle( Primary and Secondary) 4.The Liner 5.Flow Sleeve 6.Transition Piece 7.Cross Fire Tubes 8.Spark Plugs 9.Flame Detectors( Primary and Secondary)

GENERAL ELECTRIC CAN COMBUSTOR DESIGN

COMBUSTION WRAPPER AND COMBUSTION CAN COVER

COMBUSTION WRAPPER 1.The combustion wrapper is fabricated core sampling split casing that encloses the combustion system. 2.It provides a supporting surface for the combustion chamber assemblies. 3.The wrapper forms a large plenum which receives the compressor discharge air. 4.This air is directed upstream to the combustion chamber. 5.The forward face of the wrapper is slanted at 13 ̊ angle from the vertical and contains machined openings to weld the 14 combustor chamber covers. 6.The wrapper is supported by the combustion discharge casing and the turbine shaft

COMBUSTION CAN COVER 1.The combustion can cover function is to carry the combustion chamber components. 2.The flow sleeve is mounted on the combustion chamber cover.

FLOW SLEEVE 1.The flow sleeve forces the air to move upstream forming a uniform air jacket around the liner for precise combustion and cooling function among the 14 chamber.

LINER 1.The liner is the core of the combustion system. 2.Inside the liner air and fuel are mixed and burnt providing hot gases. 3.The liner is mounted on the flow sleeve at forward side by three liner supports. 4.And supported at the aft by inserting the liner inside the transition piece. 5.This configuration allows thermal expansion of the liner.

SPRING SEALS 1.Spring seals located at the aft end of the liner to prevent the combustion discharge air from leaking into the hot gas pan

PARTS OF LINER The liner consists of : 1.Liner body 2.Multi nozzle cap assembly 3.The venturi

1.The parts of the liner are assembled together by rivets. 2.Combustion air flows into the liner through various locations. 3.Primary combustion air flows through the primary gas tips. 4.Air enters from metering holes for combustion functions. 5.Secondary combustion air enters through the center body. 6.Dilution air enters the liner through three dilution air holes at the aft side of the liner. 7.Due to the extremely high temperature encountered inside the liner, all the surfaces which are exposed to the flame are protected by a thermal barrier coating. 8.The combustion liner is also protected by film cooling as air flows through the liner cooling rings to make an air film adjacent to the liner surface. 9.The air film keeps the hot gas away from the liner metal. 10.The liner cap is protected by film cooling and back side impringement cooling. 11.The venturi is cooled by backside impringement cooling.

CROSS FIRE TUBE All combustion chamber Is connected by means of cross fire tube. This tube enable the flame to propagate from one chamber to the another.

DETAILED CROSS FIRE TUBE The cross fire tube consists of : 1.Male part 2.Female part Each is inserted into the cross fire tube collar. And held on the bracket on the flow sleeve by the cross fire tube retainer. All cross fire tubes are surrounded by cross fire outer tube. These tubes connect the combustion chamber outer covers together. Packing is installed to minimize leakage and held by flanges on both sides of the tube Outer tubes are prevented from sliding by split retainer mounted on the flanges.

COMBUSTION ZONES As the DLN system focuses on two combustion zones, fuel is injected to the combustion chamber through the primary and secondary fuel nozzle. The primary fuel nozzle is functionally integrated with the combustion chamber end cover and provides a flange in the center for the secondary nozzle mounting. Fuel is injected into the primary zone through 6 identical nozzles. Gas fuel is the primary nozzle assembly through the fuel gas connection flange and is rather through internally meshed passages to the orifice located in the gas tip. Atomizing air is also introduced through the same passages to the primary zone through multiple holes on each of the gas tips. Water is injected to the primary water injection manifold and then the distributed to 6 nozzles through piping to each one of the fuel oil flange and tip assemblies. Liquid fuel is supplied to liquid fuel distribution valve to equally distribute the fuel across the 6 nozzles.

Specially, on start up the fuel flows through the piping to the primary zone to the liquid fuel tip located at the center of the gas tip. The secondary nozzle features as a ply flange for the secondary gas fuel which is injected into the secondary premixed zone through multiple holes. A small amount of secondary gas is injected after the secondary Swirler. This amount of gas is called secondary gas which promote secondary flame stability. Transfer gas returns the transient operation is applied to the relevance supply flange and is injected before the secondary Swirler Liquid fuel and water flow from the inlet flanges is to the combustion zone were they are injected at the aft tip of the secondary nozzle assembly. Combustion is initiated by means of two spark plug mounted on the 11th and 12th combustion chamber.

SPARK PLUGS

SPARK PLUG The spark plug is mounted on the ball joint. This joint allows the adjustments of the spark plug relative to the liner. On the DLN-1 combustion system spark plugs remain inside the liner through out all the operation. For startup and primary zone reignition function,once the flame is started in the chambers it propagates to the other chamber through cross fire tubes. Flame is detected in the combustion chamber through UV flame detectors mounted on four chambers -14,1,2,3 combustion chamber. As the DLN-1 system features two combustion zones flame is detected by 4 flame detectors in each zone. The flame in the primary zone is detected by flame detectors mounted on the inclined mounting pads on the combustion chamber covers. This detectors are inclined to detect the flame through one of the metering holes around the liner body.

FLAME DETECTORS

The secondary flame detectors are mounted on the secondary nozzle flame flange. Flame is detected in the secondary zone through view port in the secondary Swirler. Transition piece on the interface between the combustion and turbine section. They direct the hot gases from the liners into the turbine 1 st stage nozzle assembly. The 1 st stage nozzle entrance are divided into 14 equal areas receiving the hot gas flows. Due to the extremely high temperature of the passing hot gases the inside surface of the transition piece are coated with thermos barrier coating. Cooling air is introduced by allowing compressor discharge air through the vent plates to the cooling holes machined on the transition piece aft end. The transition pieces are sealed on the outer and inner walls of the 1 st stage nozzle by the outer and inner seals. This seals are inserted into grooves on the 1 st stage nozzle to minimize compressor discharge air leakage into the hot gas pan.

The side of the transition piece are sealed by side seals. Side seals are held in position by side seal retainer blocks. This blocks are mounted on the 1 st stage nozzle retainer ring. Transition pieces are supported at the aft side by aft mounting bracket which is mounted on the 1 st stage nozzle assembly. Each transition piece is supported at the forward side by support clamp. This support clamp is mounted on the compressor discharge casing.

CAN-ANNULAR

LITERATURE SURVEY Design and Analysis of Annular Combustion Chamber of a Low by Pass Turbofan Engine in a Jet Trainer Aircraft In this the design of an annular combustion chamber of a low by pass turbofan engine in a jet trainer aircraft is taken as a medium for analysis. The model is constructed using the SIEMENS NX8.0 software and the analysis is done using ANSYS 14.5 software. The analysis of air fuel mixture, combustion turbulence and chemical kinetics is carried out. An efficient combustion chamber was delivered with model being analyzed aerodynamically and after optimization of the geometry based on the results.

Design and Analysis of Annular Combustion Chamber of a Low by Pass Turbofan Engine in a Jet Trainer Aircraft Authors: C. Priyant Mark, A. Selwyn 4 March,2016 In this the design of an annular combustion chamber of a low by pass turbofan engine in a jet trainer aircraft is taken as a medium for analysis. The model is constructed using the SIEMENS NX8.0 software and the analysis is done using ANSYS 14.5 software. The analysis of air fuel mixture, combustion turbulence and chemical kinetics is carried out. An efficient combustion chamber was delivered with model being analyzed aerodynamically and after optimization of the geometry based on the results.

CFD Analysis of Gas Turbine Combustor Primary Zone Using Different Axial Swirler Configurations Authors: Prasanna Gouda, K. Srinivasan, G. Siva Ramakrishna, K.S. Shashisekar June 2016 In this analysis, the effects of using different geometry swirlers in combustor is described. The swirlers are used to create recirculation zone to stabilize the flame and to increase the rate of air fuel mixture to improve combustion. This analysis motive is to create the large swirl velocities which in turn produces the high level of turbulence kinetic energy and thus produce better recirculation zone. On comparing the flat vane swirl with the curved vane swirl, the curved vane proved to produce high level of performance even though both have the same geometric swirl number. The reason for the improved performance on analysis proves that curved vane swirl allows more mass flow due to less blockage and allow improved mixing in combustion chamber.

A Swirler Stabilized Combustion Chamber for a Gas Micro Gas Turbine Fueled with Natural Gas Authors: Ambrish Babu, K.K.Arun, Anandanarayanan 2012 In this paper the combustion chamber reliability, durability and achievement of flame stabilization is being discussed. The RSM turbulence model and β-PDF equilibrium model was used to analyze the inner flow of the combustor and to account for turbulent combustion process. The flow inside the combustor was reproduced using heat transfer model instead of the non-heat transfer model as they simulated radiation and linear conduction

Combustion Characteristics of an Annular Type meso-scale Combustor Authors: Yosuke Suenaga, Hideki Yanaoka, Yoichi Takeda, Mamoru Kikuchi 22 June 2016 In this the design of meso scale combustor and its analysis were done and compared with the other types of meso scale combustor to design the efficient combustor. The C3h8 fuel with air as oxidizer is supplied to the inner and outer tubes and the flame structure was analyzed by measuring the temperature from the thermocouples. On experimentation the values of the efficient combustor for the heat loss rate and energy loss rate were found to be 0.37 and 0.57 respectively.

Experimentation of flame stabilization using Strong Swirl for afterburner Application Authors: Dr. K.M. Parammasivam, Mr. D. Devanathan 2016 This paper presents a design of strong swirl that could be used for flame stabilization in the combustor. The author emphasis the use of 45-degree angled swirl. The swirl is designed and analysed for various operating conditions for reactants entering the control volume. The CFD analysis is done to obtain optimized result design and then the swirl is fabricated with stainless steel (SS304) with vertical milling machine and then welding. The swirl is tested to find it is effect over flame stabilization.

Computational Simulation and effect of Swirl angle on NOx generation of 2D swirl burner in gas turbine Authors: Surya Kumar, K. M. Pandey August The author prescribes the use of Swirler to create small scale turbulence in the fuel. And the efficiency of the combustion and control of the exhaust gases improves with uniform fuel distribution. A mesh of the Swirl is worked out in Gambit with quadratic cells. The author modelled Swirl and used k-ε model to perform a steady, turbulent,2-D Swirling flow. On analysis, be found that 45-degree angle vane proved to be ultimate and provided better flow pattern mixing and temperature in swirl burner compared to another swirl design.

CFD modelling of an aero gas turbine combustor for a small gas turbine Engine Authors: K. Sreenivasarao, Prof.Mr S.K. Bhatti January This paper deals with CFD analysis of small gas turbine combustor in ANSYS, CFX software and to study the quality of temperature distribution and combustor efficiency. The predicted theory and the experiments performed yielded similar results. It emphasis that CFD codes provide qualitative and reasonable quantitative information which could be effectively used in combustor design optimization. All the things were analysed using a k- ε turbulent flow model.

Combustion chamber Design And performance of micro gas turbine applications. Authors: Ibrahim I. Enagi, Khaled Al-attab, Z.A. Zainal November 2017 This paper is about the design of two staged micro gas turbine in solid works software and to analyse the model in Ansys fluent. The author obtained an optimum combustion chamber design by testing Various geometries. Therefore, an optimized design obtained from species transport combustion model.

Large eddy current simulation of combustion dynamics of bean premixed swirl stabilized combustion Ying Huang, Hong-Gye Sung, Shih-Yang Hsieh, and Vigor Yang September-October 2003 The author provides detailed investigation about the interaction between the turbulent flow motions and oscillatory combustion of a swirl stabilized combustor. He says that the process responsible for combustion in stability is identified as acoustic wave motion and vortex shielding and flame oscillations. Therefore, a passive and active control strategies must be adopted for combustion instabilities in gas turbine.

Conclusion : The inference obtained from the papers of the literature review is : 1.Annular combustion chamber geometry optimization is discussed. 2.Axial Swirler configuration details were studied.

swirl parameter Swirl angle Ѳ = 30 ̊ Channel width (H) = 12.7 mm Outer diameter( D) = 98 mm Inner diameter (d)= 50 mm Vane depth (L)= 40 mm

DESIGN – SWIRLER(30 DEGREE )