Development of Inverse Analysis of Heat Conduction and Thermal Stress for Elbow (Part I)

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Seiji Ioka ◽  
Shiro Kubo ◽  
Mayumi Ochi ◽  
Kiminobu Hojo
Keyword(s):  
Heat Conduction ◽  
Surface Temperature ◽  
Inverse Analysis ◽  
Power Plants ◽  
Fatigue Cracking ◽  
Stratified Flow ◽  
Temperature History ◽  
Inverse Heat Conduction ◽  
Analysis Method ◽  
Inner Surface

High temperature stratified flow sometimes caused thermal fatigue cracking in power plants. To prevent fatigue damage by stratified flow, it is important to know temperature distribution history in a pipe. In this study, inverse heat conduction analysis method for an elbow model was developed to estimate the inner surface temperature from the measured outer surface temperature. In the method, the transfer function database inter-relating the inner surface temperature with the outer one was used. For several patterns of the temperature history, the inverse analysis simulations were performed and the accuracy of the estimated inner surface temperature was shown.

Development of Inverse Analysis of Heat Conduction and Thermal Stress for Elbow: Part I

2013 ◽  
Author(s):  
Seiji Ioka ◽  
Shiro Kubo ◽  
Mayumi Ochi ◽  
Kiminobu Hojo
Keyword(s):  
Heat Conduction ◽  
Thermal Stress ◽  
Transfer Function ◽  
Surface Temperature ◽  
Outer Surface ◽  
Inverse Analysis ◽  
Temperature History ◽  
Analysis Method ◽  
Inner Surface ◽  
Inverse Analysis Method

Thermal fatigue may develop in piping elbow with high temperature stratified flow. To prevent the fatigue damage by stratified flow, it is important to know the distribution of thermal stress and temperature history in a pipe. In this study, heat conduction inverse analysis method for piping elbow was developed to estimate the temperature history and thermal stress distribution on the inner surface from the outer surface temperature history. In the inverse analysis method, the inner surface temperature was estimated by using the transfer function database which interrelates the inner surface temperature with the outer surface temperature. Transfer function database was calculated by FE analysis in advance. For some patterns of the temperature history, inverse analysis simulations were made. It was found that the inner surface temperature history was estimated with high accuracy.

Development of Inverse Analysis Method of Heat Conduction and Thermal Stress for Elbow—Part II

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Kiminobu Hojo ◽  
Mayumi Ochi ◽  
Seiji Ioka ◽  
Shiro Kubo
Keyword(s):  
Heat Conduction ◽  
Thermal Stress ◽  
Inverse Analysis ◽  
Maximum Stress ◽  
Fluid Temperature ◽  
Inverse Heat Conduction ◽  
Analysis Method ◽  
Inner Surface ◽  
Pressure Test ◽  
Inverse Analysis Method

An inverse heat conduction analysis method for piping elbow was developed to estimate the temperature and stress distribution on the inner surface by measuring the outer surface temperature. In the paper, the accuracy for the thermal stress calculation using the inverse heat conduction analysis method was confirmed by comparing with the reference results from normal FE heat conduction and thermal stress analyses. In the case of the measured-basis fluid temperature input from a high temperature–pressure test, the inverse analysis method estimated the maximum stress change by 7% conservative comparing with the normal FE analyses.

Inverse Analysis of In-Cylinder Gas-Wall Boundary Conditions: Investigation of a Yittria Stabilized Zirconia Thermal Barrier Coating for Homogeneous Charge Compression Ignition

2016 ◽  
Author(s):  
Ryan O’Donnell ◽  
Tommy Powell ◽  
Mark Hoffman ◽  
Zoran Filipi
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Conduction ◽  
Surface Temperature ◽  
Inverse Analysis ◽  
Fast Response ◽  
Thermal Barrier ◽  
Temperature Profiles ◽  
Inverse Heat Conduction ◽  
Cycle Efficiency

Thermal Barrier Coatings (TBC) applied to in-cylinder surfaces of a Low Temperature Combustion (LTC) engine provide opportunities for enhanced cycle efficiency via two mechanisms: (i) positive impact on thermodynamic cycle efficiency due to combustion/expansion heat loss reduction, and (ii) enhanced combustion efficiency. Heat released during combustion elevates TBC surface temperatures, directly impacting gas-wall heat transfer. Determining the magnitude and phasing of the associated TBC surface temperature swing is critical for correlating coating properties with the measured impact on combustion and efficiency. Although fast-response thermocouples provide a direct measurement of combustion chamber surface temperature in a metal engine, the temperature and heat flux profiles at the TBC-treated gas-wall boundary are difficult to measure directly. Thus, a technique is needed to process the signal measured at the sub-TBC sensor location and infer the corresponding TBC surface temperature profile. This task can be described as an Inverse Heat Conduction Problem (IHCP), and it cannot be solved using the conventional analytic/numeric techniques developed for ‘direct’ heat flux measurements. This paper proposes using an Inverse Heat Conduction solver based on the Sequential Function Specification Method (SFSM) to estimate heat flux and temperature profiles at the wall-gas boundary from measured sub-TBC temperature. The inverse solver is validated ex situ under HCCI like thermal conditions in a custom fabricated radiation chamber where fast-response thermocouples are exposed to a known heat pulse in a controlled environment. The analysis is extended in situ, to evaluate surface conditions in a single-cylinder, gasoline-fueled, HCCI engine. The resulting SFSM-based inverse analysis provides crank angle resolved TBC surface temperature profiles over a host of operational conditions. Such metrics may be correlated with TBC thermophysical properties to determine the impact(s) of material selection on engine performance, emissions, heat transfer, and efficiencies. These efforts will also guide next-generation TBC design.

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