Probabilistic Assessment of Combustor Liner Design

1995 ◽  
Author(s):  
Shantaram S. Pai ◽  
Christos C. Chamis
Keyword(s):  
Thermal Load ◽  
Mechanical Load ◽  
Coefficient Of Thermal Expansion ◽  
Probabilistic Assessment ◽  
Vibration Frequencies ◽  
Combined Stress ◽  
Liner Material ◽  
Load Profile ◽  
Local Stresses ◽  
Combustor Liner

A typical hot structural component within an engine such as composite combustor liner is computationally simulated and probabilistically evaluated in view of the numerous uncertainties associated with the structural, material, and thermo-mechanical load variables (primitive variables) that describe the combustor. The combustor is evaluated for buckling (eigenvalue) loads, vibration frequencies, and local stresses. Results show that the scatter in the combined stress is not uniform along the length of the combustor. Furthermore, coefficient of thermal expansion, hoop modulus of the liner material, and the thermal load profile dominate stresses near the support and the intermediate location of the combustor liner. However, the liner thickness, the liner material hoop modulus, and pressure load profile have significant impact on stresses near the free end of combustor.

scholarly journals Quantification of Thermal-Structural Uncertainties in Engine Combustor Composite Liners

1997 ◽  
Author(s):  
Shantaram S. Pai ◽  
Christos C. Chamis
Keyword(s):  
Mechanical Load ◽  
Coefficient Of Thermal Expansion ◽  
Thermal Gradients ◽  
Combined Stress ◽  
Liner Material ◽  
Shear Moduli ◽  
Local Stresses ◽  
Structural Uncertainties ◽  
Combustor Liner ◽  
Composite Liners

A typical hot structural component within an engine such as composite combustor liner is computationally simulated and probabilistically evaluated in view of the numerous uncertainties associated with the structural, material, and thermo-mechanical load variables (primitive variables) that describe the combustor. The combustor is evaluated for local stresses. Results show that the scatter in the combined stress near the support is significantly dependent upon the uncertainties in the through thickness thermal gradients, the liner material thickness, the coefficient of thermal expansion, and the axial and both the axial and shear moduli.

scholarly journals Influence of Miller cycle on thermal load of high-boosted diesel engine

2022 ◽  
Vol 14 (1) ◽  
pp. 168781402110709
Author(s):  
Ming Wen ◽  
Yufeng Li ◽  
Xiaojuan Li ◽  
Jinlong Liu ◽  
Juting Fan
Keyword(s):  
Thermal Load ◽  
Consumption Rate ◽  
Mechanical Load ◽  
Base Case ◽  
Miller Cycle ◽  
Intake Valve ◽  
Inlet Valve ◽  
Exhaust Temperature ◽  
Fuel Consumption Rate ◽  
Main Factors

With the increase of the engine intensified degree, mechanical load and thermal load become to the two main factors limiting the engine to intensify. Application of Miller cycle, which can be realized by late intake valve closing (LIVC) and deeper late intake valve closing (DLIVC), has the potential to reduce the effective CR, mechanical load, and thermal load. In this paper, the effects of LIVC and DLIVC on the mechanical load and thermal load of a boosted DI diesel are experimentally compared. Compared to the original base case, the average cylinder temperature of LIVC and DLIVC is reduced by 90 and 52 K. The exhaust temperature of LIVC and DLIVC decreased by 26 and 14 K, and the maximum combustion pressure of LIVC and DLIVC decreased by 1.6 and 9.7 bar. The pumping losses of LIVC and DLIVC are reduced by more than 25%, while the actual cycle power does not decrease due to the late closing of the inlet valve. The fuel consumption rate decreased from 250.1 g/kWh of base case to 240 g/kWh of LIVC, reduced by 4.0%. The indicated thermal efficiency increased from 41.9% of base case to 43.7% and 42.5% of LIVC and DLIVC. Miller loss is only 2.55% with Miller inlet phase.

Studying the Critical Buckling Load of FG Beam Using ANSYS

2021 ◽  
Vol 1039 ◽  
pp. 7-22
Author(s):  
Khetam S. Ateah ◽  
Luay S. Alansari
Keyword(s):  
Power Law ◽  
Thermal Load ◽  
Mechanical Load ◽  
Functionally Graded ◽  
Thickness Ratio ◽  
Buckling Load ◽  
Mode Number ◽  
Critical Buckling Load ◽  
Fg Beam ◽  
Power Law Index

In this article, the critical buckling load of functionally graded beam is calculated using ANSYS APDL Software (version 17.2) under mechanical and thermal load. In mechanical load, the effects of length to thickness ratio, power law index and mode number on the non-dimension critical buckling load of fixed-fixed and fixed-free FG beam. The results show that the length to thickness ratio is not effect on the non-dimension critical buckling load while the power law index and mode number effect on the non-dimension critical buckling load. In thermal load, the critical buckling load for fixed-fixed and pinned-pinned FG beam depend on length to thickness ratio, power law index and mode number. The results show that the critical buckling load increases with decreasing length to thickness ratio.

Microstructural Finite Element Modeling and Simulation on Al–MgO Composites

2015 ◽  
Vol 12 (05) ◽  
pp. 1550030 ◽  
Author(s):  
Satyanarayan Patel ◽  
Rahul Vaish ◽  
Vishal Singh Chauhan ◽  
Chris Bowen
Keyword(s):  
Finite Element ◽  
Volume Fraction ◽  
Filler Content ◽  
Coefficient Of Thermal Expansion ◽  
Object Oriented ◽  
Stress And Strain ◽  
Thermal And Mechanical Properties ◽  
Element Analysis ◽  
Local Stresses ◽  
Properties Of Composites

Object Oriented Finite Element Analysis (OOF2) is used to predict the thermal and mechanical properties of Al – MgO composites. In this work, three compositions of composites containing 5%, 10% and 15% MgO (by volume) are studied. The influence of MgO volume fraction is examined in terms of effective Young's modulus and coefficient of thermal expansion of the composites. In addition, the stress and strain contours are plotted, which are helpful to understand the mechanical behavior of these composites. It is noted that the properties of composites are improved because of the presence of MgO . However, local stresses increase with filler content.

Simulation of Combustor Damage Mechanisms and Material System Performance via a Sub-Element Configured Specimen Test

2011 ◽  
Author(s):  
Nagaraja Rudrapatna ◽  
Benjamin H. Peterson
Keyword(s):  
Gas Turbine ◽  
Thermal Fatigue ◽  
Bond Coat ◽  
Test Method ◽  
Material System ◽  
Engine Operation ◽  
Damage Mechanisms ◽  
Liner Material ◽  
Material Systems ◽  
Combustor Liner

Modern gas turbine combustors are made of high temperature alloys, employ effusion cooling and are protected by a Thermal Barrier Coating (TBC). Standard material characterization tests such as creep, oxidation and low cycle fatigue are indicators of a material’s potential performance but they neither fully represent the combustor geometric/material system nor fully represent the thermal fatigue conditions a combustor is subjected to during engine operation. Combustor rig tests and/or engine cyclic endurance tests to determine the suitability of new material systems for combustors are time consuming and costly. Therefore, a simple test method for screening material systems under representative combustor conditions is needed. This experimental system was recently developed at Honeywell Aerospace to characterize various gas turbine combustor damage mechanisms and assess state-of-the-art and developmental materials. A configured specimen is fabricated using materials and processes similarly to actual combustor hardware, including sheet metal forming, welding, TBC coating, and effusion hole laser drilling. The configured specimen is cyclically exposed to hot spot thermal gradients typically experienced by fielded hardware using a jet-fueled burner and heated cooling air. Damage mechanisms simulated include bond coat oxidation, TBC spallation, thermal fatigue and distortion. A summary of these damage mechanisms and lessons learned from test development are presented. Results from recent combustor liner, bond coat, and top coat material modifications are also discussed. The effect of combustor liner material creep and thermal fatigue resistance, bond coat composition and processing, and TBC composition and structure on combustor durability is presented.

Predicted Thermal Mismatch Stresses in a Cylindrical Bi-material Assembly Adhesively Bonded at Its Ends

1997 ◽  
Vol 64 (1) ◽  
pp. 15-22 ◽  
Author(s):  
E. Suhir
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Coefficient Of Thermal Expansion ◽  
Stress Model ◽  
Adhesively Bonded ◽  
Thermal Mismatch ◽  
Adhesive Material ◽  
Thermally Induced ◽  
Local Stresses ◽  
Material Assembly

A simple analytical stress model, based on the strength-of-materials approach, is developed for the evaluation of thermally induced shearing stresses in a long cylindrical bi-material assembly adhesively bonded at its ends and subjected to the change in temperature. The emphasis is on the interaction of the “global” thermal mismatch stresses, counted with respect to the mid cross section of the assembly as a whole, and the “local” stresses, counted with respect to the mid cross sections of the bonded regions. The effect of the coefficient of thermal expansion of the adhesive material itself is also considered. We show also how to evaluate the fundamental frequency of vibrations of the inner cylinder with consideration of the thermally induced tension, if any.

Constitutive Model Development for Thermo-Mechanical Fatigue Response Simulation of Haynes 230

2012 ◽  
Author(s):  
Raasheduddin Ahmed ◽  
Mamballykalathil Menon ◽  
Tasnim Hassan
Keyword(s):  
Stress Response ◽  
Constitutive Model ◽  
Kinematic Hardening ◽  
Isotropic Hardening ◽  
Large Set ◽  
Mean Stress ◽  
Liner Material ◽  
Mechanical Fatigue ◽  
Combustor Liner ◽  
Mean Strain

Turbine engine combustor components are subject to thermo-mechanical fatigue (TMF) during service. The combustor liner temperatures can sometimes reach as high as 1800°F. An accurate estimate of the strains at critical locations in the combustor liner is required for reliable lifing predictions. This demands the need for a detailed analysis of the TMF responses and a robust constitutive model capable of predicting the same. A large set of experiments have been carried out on the liner material, a nickel based alloy, HA 230, in an effort to understand its thermo-mechanical fatigue constitutive response. The out-of-phase strain-controlled TMF experiments with a negative mean strain show a positive mean stress response, while the in-phase TMF experiments with a positive mean strain show a negative mean stress response. A Chaboche based viscoplastic constitutive model is under development. It will have several essential features such as nonlinear kinematic hardening, isotropic hardening, strain range dependence, rate dependence, temperature dependence and static recovery. The constitutive model being developed for accurately calculating the stress-strain response is being carried out with the final objective of predicting the strains in an actual combustor liner in service through finite element simulation for fatigue lifing.

Thermoviscoelastic behavior of a short fiber-reinforced polymer hollow cylinder accounting for porosity

2016 ◽  
Vol 51 (19) ◽  
pp. 2779-2791 ◽  
Author(s):  
Hong-Liang Dai ◽  
Ting Dai ◽  
Wei-Feng Luo
Keyword(s):  
Hollow Cylinder ◽  
Integral Transform ◽  
Mechanical Load ◽  
Coefficient Of Thermal Expansion ◽  
Short Fiber ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Cylindrical Structures ◽  
Reinforced Polymer ◽  
Hollow Cylinders

In this paper, thermoviscoelastic behavior of a hollow cylinder made of short fiber-reinforced polymer considering porosity is investigated by an analytical method. Material properties, except the Poisson’s ratio and coefficient of thermal expansion, are assumed to be changed with the volume of constituents and porosity. Utilizing the finite Hankle integral transform and Laplace transform, analytical solutions for thermoviscoelastic behaviors of short fiber-reinforced polymer hollow cylinders under thermal and mechanical loads are obtained. Numerical examples show the influences of thermal load, mechanical load, and material porosity on the thermoviscoelastic behaviors of short fiber-reinforced polymer cylindrical structures.

scholarly journals Newly Developed Thermal Load Profile for Enhancement in Hot Water System

2021 ◽  
Vol 79 (2) ◽  
pp. 83-94
Author(s):  
Norazlianie Sazali ◽  
Munirah Nawi ◽  
Saiful Anwar Che Ghani ◽  
Maurice Kettner
Keyword(s):  
Thermal Load ◽  
Water System ◽  
Feedback Mechanism ◽  
Hot Water ◽  
Load Profile ◽  
Flexible System ◽  
Laboratory Setup ◽  
System A ◽  
Loop Feedback ◽  
Water Simulation

In recent years with the advancement of technologies, the demand of a reliable and flexible hot water system has increased tremendously. A reliable system includes several critical points which are the degree of safety that a system can offer, the conservation of the energy used and the issue of cost saving. While a flexible system must provide the flexibility in the control of the output from a system desired by the consumers itself. This paper reported on newly developed system for hot water that will greatly benefit consumer. It focuses on building an extension of the cyber physical system in the existing system with purposes of implementing a thermal load profile for consumer who use the hot water system in their daily life. The implementation of the thermal load profile to the system is significant especially in conserving the energy used in the system simultaneously saving any related cost to operate the system. Based on the implemented thermal load profile, the system works in maintaining an output of thermal energy from the hot water supplied to the consumer at a certain value. In addition, it also allows flexibility in controlling the desired temperature by consumers. This new system is simulated in a test bench in the form of laboratory setup. The system uses a control loop feedback mechanism, which means that it will continuously regulate the temperature and mass flow rate of the flowed water in the pipeline for the consumer hot water simulation based on the calculated difference of the actual supplied values and the set values. With the use of standard devices and actuators to drive the system, a robust system can be realized.

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