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.

High-output diesel engine heat transfer: Part 1 - comparison between piston heat flux and global energy balance

2021 ◽  
pp. 146808742110170
Author(s):  
Eric Gingrich ◽  
Michael Tess ◽  
Vamshi Korivi ◽  
Jaal Ghandhi
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Diesel Engine ◽  
Surface Temperature ◽  
Fast Response ◽  
Temperature Data ◽  
Start Of Injection ◽  
Local Measurements ◽  
Surface Temperature Data ◽  
High Output

High-output diesel engine heat transfer measurements are presented in this paper, which is the first of a two-part series of papers. Local piston heat transfer, based on fast-response piston surface temperature data, is compared to global engine heat transfer based on thermodynamic data. A single-cylinder research engine was operated at multiple conditions, including very high-output cases – 30 bar IMEPg and 250 bar in-cylinder pressure. A wireless telemetry system was used to acquire fast-response piston surface temperature data, from which heat flux was calculated. An interpolation and averaging procedure was developed and a method to recover the steady-state portion of the heat flux based on the in-cylinder thermodynamic state was applied. The local measurements were spatially integrated to find total heat transfer, which was found to agree well with the global thermodynamic measurements. A delayed onset of the rise of spatially averaged heat flux was observed for later start of injection timings. The dataset is internally consistent, for example, the local measurements match the global values, which makes it well suited for heat transfer correlation development; this development is pursued in the second part of this paper.

scholarly journals Coaxial Thermocouples for Heat Transfer Measurements in Long-Duration High Enthalpy Flows

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5254
Author(s):  
Shizhong Zhang ◽  
Qiu Wang ◽  
Jinping Li ◽  
Xiaoyuan Zhang ◽  
Hong Chen
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Surface Temperature ◽  
Thermal Effusivity ◽  
Fast Response ◽  
Test Time ◽  
Physical Parameters ◽  
Fourier Number ◽  
High Enthalpy ◽  
Long Duration

Coaxial thermocouples have the advantages of fast response and good durability. They are widely used for heat transfer measurements in transient facilities, and researchers have also considered their use for long-duration heat transfer measurements. However, the model thickness, transverse heat transfer, and changes in the physical parameters of the materials with increasing temperature influence the accuracy of heat transfer measurements. A numerical analysis of coaxial thermocouples is conducted to determine the above influences on the measurement deviation. The minimum deviation is obtained if the thermal effusivity of chromel that changes with the surface temperature is used to derive the heat flux from the surface temperature. The deviation of the heat flux is less than 5.5% when the Fourier number is smaller than 0.255 and 10% when the Fourier number is smaller than 0.520. The results provide guidance for the design of test models and coaxial thermocouples in long-duration heat transfer measurements. The numerical calculation results are verified by a laser radiation heating experiment, and heat transfer measurements using coaxial thermocouples in an arc tunnel with a test time of several seconds are performed.

Nonlinear Inverse Heat Conduction With a Moving Boundary: Heat Flux and Surface Recession Estimation

1999 ◽  
Vol 121 (3) ◽  
pp. 708-711 ◽  
Author(s):  
V. Petrushevsky ◽  
S. Cohen
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Fourier Series ◽  
Heat Conduction ◽  
Moving Boundary ◽  
Heat Conduction Problem ◽  
Inverse Heat Conduction Problem ◽  
Variable Order ◽  
Inverse Heat Conduction ◽  
One Dimensional

A one-dimensional, nonlinear inverse heat conduction problem with surface ablation is considered. In-depth temperature measurements are used to restore the heat flux and the surface recession history. The presented method elaborates a whole domain, parameter estimation approach with the heat flux approximated by Fourier series. Two versions of the method are proposed: with a constant order and with a variable order of the Fourier series. The surface recession is found by a direct heat transfer solution under the estimated heat flux.

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.

Inverse Heat Conduction Errors From Temperature Bias in Thin Film Sensors: Effect of Contact Resistance

2011 ◽  
Author(s):  
Keith A. Woodbury ◽  
Jonathan W. Woolley
Keyword(s):  
Thin Film ◽  
Heat Flux ◽  
Heat Conduction ◽  
Contact Resistance ◽  
Surface Temperature ◽  
Temperature Error ◽  
Lead Wire ◽  
Inverse Heat Conduction ◽  
Detailed Model ◽  
Thin Film Sensors

Thin platinum resistance thermometers (herein called thin film sensors) are often used in applications where rapid measurements of surface temperature are required. These gages are typically vapor deposited onto a non-conducting substrate surface and electrically connected with small wires through access holes to the surface. The time response of the gage is measured in milliseconds and surface temperature data obtained with this gage is often combined with a pseudo-inverse heat conduction algorithm to provide information about the surface heat flux. However, the thermal mass of the connecting wires, though small in absolute terms, is large compared to that of the thin film, and the capacitive effect of this mass gives rise to distortions in the temperature field in the area of the gage, resulting in a small error in the sensed temperature. This temperature error, when used in the inversion for heat flux, also results in an error. In this report, a detailed model of a particular thin film gage is used to compute the response of the sensor to supposed heating conditions. The effect of contact resistance between the parent material and the lead wire connections is investigated. The response of the sensor, with and without the contact resistance, and the undisturbed surface temperature are compared to estimate the temperature error. Finally, the error in the computed heat flux is determined. A simple approximate technique based on superposition is applied to account for the sensor dynamics and correct the error in the estimated heat flux.

Hyperbolic Heat Conduction Equation for Materials With a Nonhomogeneous Inner Structure

1990 ◽  
Vol 112 (3) ◽  
pp. 555-560 ◽  
Author(s):  
W. Kaminski
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Conduction ◽  
Physical Meaning ◽  
Heat Conduction Equation ◽  
Hyperbolic Heat Conduction ◽  
Temperature Profiles ◽  
Using Data ◽  
Penetration Time

The physical meaning of the constant τ in Cattaneo and Vernotte’s equation for materials with a nonhomogeneous inner structure has been considered. An experimental determination of the constant τ has been proposed and some values for selected products have been given. The range of differences in the description of heat transfer by parabolic and hyperbolic heat conduction equations has been discussed. Penetration time, heat flux, and temperature profiles have been taken into account using data from the literature and our experimental and calculated results.

Estimation of the Transient Surface Temperature and Heat Transfer Coefficient of Convective Cooling for Large Slab and Long Cylinder by Using an Inverse Heat Conduction Method

2013 ◽  
Author(s):  
Ramin Soujoudi ◽  
Antonio Campo
Keyword(s):  
Heat Transfer ◽  
Heat Conduction ◽  
Surface Temperature ◽  
Series Solution ◽  
Initial Temperature ◽  
Numerical Solutions ◽  
Thermal Boundary Condition ◽  
Heat Equations ◽  
Inverse Heat Conduction ◽  
Long Cylinder

Inverse heat conduction method is a technique to determine heat flux and surface temperature on an inaccessible surface of wall by measuring the temperature on an accessible boundary. The objective of this paper is to develop a method by which stable prediction of heat transfer on an inaccessible boundary could be obtained without altering the thermal boundary condition that would have existed were sensor not present. In this work, three points backward finite difference applied to the 1-D heat equation for large slab and long cylinder with constant thermophysical properties and uniform initial temperature. The numerical solutions of the heat equations are performed with symbolic Maple software. It is demonstrated that approximate temperature distributions for the three bodies are equivalent to analytical solution using first term series solution. It is also shown that the series solution converge rapidly for long times, and for Fo > 0.2, ony the first term of the series nned to be retained for 2% accuracy.

Application of Inverse Heat Conduction Method and Method of Lines in Spray Cooling of Heated Surface

2016 ◽  
Author(s):  
Ramin Soujoudi
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Coefficient ◽  
Heat Conduction ◽  
Transfer Coefficient ◽  
Heated Surface ◽  
Method Of Lines ◽  
Spray Cooling ◽  
Approximation Technique ◽  
Inverse Heat Conduction

This paper investigates application of Method of Lines (MOL) and Inverse Heat Conduction techniques in spray cooling process. A flat face of a heated cylinder is cooled by using a nozzle spray and using room temperature water as a cooling fluid. The numerical analysis is done using MOL to estimate exposed surface temperature, surface heat flux, and convection heat transfer coefficient [3],[4]. Since there is no exact solution to verify the approximation result, for the verification purpose and accuracy of the result, the numerical result from this study is compared to other approximation results with experimental research done by Chen-Lee and Qiao-Chandra [1]. The results illustrate that disparity between the outcome of MOL and the one generated by Chen and Lee’s raw data is very insignificant throughout the whole time domain. This discrepancy between these two estimated results proves that MOL is a very reliable approximation technique compared to other finite element methods which require a finer mesh size and significant amount of calculations[2],[5]. However, comparing the results obtained through MOL with Qiao and Chandra shows that the difference between the estimated heat transfer coefficient and estimated heat flux converges rapidly for the short times of 0 < t < 60, but as the time passes, the MOL approximation results diverge slowly until it reaches its maximum value at ninety seconds, and the variance remains almost constant for the rest of the time period.

Inverse Heat Conduction Using Measured Back Surface Temperature and Heat Flux

2010 ◽  
Vol 24 (1) ◽  
pp. 95-103 ◽  
Author(s):  
Jianhua Zhou ◽  
Yuwen Zhang ◽  
J. K. Chen ◽  
Z. C. Feng
Keyword(s):  
Heat Flux ◽  
Heat Conduction ◽  
Surface Temperature ◽  
Back Surface ◽  
Inverse Heat Conduction
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