Calculation of Heat Flux Integral Length Scales from Spatially-Resolved Surface Temperature Measurements in an Engine

Boggs, David L.; Borman, Gary L.

doi:10.4271/910721

Cited by 11 publications

(7 citation statements)

References 23 publications

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“…Namely, the intake and combustion chamber geometry impart flow characteristics such as tumble and swirl on the intake charge, which increase the turbulence intensity (Re values) within the cylinder and directly impact heat transfer. Boggs and Borman [90] demonstrated that increasing in-cylinder turbulence by introducing tumble or swirl resulted in increases in peak heat flux in a motoring engine by 70%, with Overbye et al [11] showing a similar relationship between turbulence and heat transfer in a motored CFR engine. Mean gas velocities within the cylinder have also been seen to double as a result of using a shrouded intake valve versus an unshrouded valve [85].…”

Section: Effect Of Structured Flowsmentioning

confidence: 99%

The Influence of Thermal Barrier Coating Surface Roughness on Spark-Ignition Engine Performance and Emissions

Memme

Wallace

2012

ASME 2012 Internal Combustion Engine Division Fall Technical Conference

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The effects on heat transfer of piston crown surface finish and use of a metal based thermal barrier coating (TBC) on the piston crown were studied in an SI engine. Measured engine parameters such as power, fuel consumption, emissions and cylinder pressure were used to identify the effects of the coating and its surface finish. Two piston coatings were tested: a baseline copper coating and a metal TBC. Reducing surface roughness of both coatings increased in-cylinder temperature and pressure as a result of reduced heat transfer through the piston crown. These increases resulted in small improvements in both power and fuel consumption, while also having measurable effect on emissions. Oxides of nitrogen emissions were increased while total hydrocarbon emissions were decreased. Improvements attributed to the TBC were found to be small, but statistically significant. At an equivalent surface finish, the TBC performed better than the baseline copper finish.iii

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Section: Effect Of Structured Flowsmentioning

confidence: 99%

The Influence of Thermal Barrier Coating Surface Roughness on Spark-Ignition Engine Performance and Emissions

Memme

Wallace

2012

ASME 2012 Internal Combustion Engine Division Fall Technical Conference

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“…The wall temperature and the heat flux are measured and calculated using thin film Resistance Temperature Detectors (RTDs). These heat flux sensors have also been used in [1,3,4,5].…”

Section: Introductionmentioning

confidence: 99%

“…The wall temperature and the heat flux are measured and calculated using thin film Resistance Temperature Detectors (RTDs). These heat flux sensors have also been used in [1,3,4,5].The heat transfer models used in current engine simulation software are mostly based on the models of Annand [6] or Woschni [7]. These models have been developed for a one-zone combustion model.…”

mentioning

confidence: 99%

Studying the Effect of the Flame Passage on the Convective Heat Transfer in a S.I. Engine

Cuyper

Broekaert

Nguyen

et al. 2017

SAE Technical Paper Series

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Engine optimization requires a good understanding of the in-cylinder heat transfer since it affects the power output, engine efficiency and emissions of the engine. However little is known about the convective heat transfer inside the combustion chamber due to its complexity. To aid the understanding of the heat transfer phenomena in a Spark Ignition (SI) engine, accurate measurements of the local instantaneous heat flux are wanted. An improved understanding will lead to better heat transfer modelling, which will improve the accuracy of current simulation software. In this research, prototype thin film gauge (TFG) heat flux sensors are used to capture the transient in-cylinder heat flux within a Cooperative Fuel Research (CFR) engine. A two-zone temperature model is linked with the heat flux data. This allows the distinction between the convection coefficient in the unburned and burned zone. The experimental time-resolved convection coefficient is then calculated by deriving the moment of flame arrival. The convection coefficient contains all the information of the driving force of the convective heat transfer. The work focusses on the effect of the flame passage on the convective heat transfer. IntroductionA better understanding of the heat transfer phenomena inside the combustion chamber is key towards improving engine efficiency. The knowledge of the in-cylinder heat loss is gaining importance due to the trend of downsizing which increases the engine load and hence the heat loss. According to [1] up to 10% and according to [2] up to 15% of the fuel energy is lost due to in-cylinder heat transfer.Although an important process, recent heat transfer research is lacking. This can be attributed to the difficulty of performing accurate heat transfer measurements inside the combustion chamber. This environment is corrosive and characterized by high temperature and pressure oscillations demanding a robust and fast heat flux sensor.The main mode of heat transfer in an SI engine is convection. Due to the absence of soot particles no radiative heat transfer takes place except in diesel engines [1]. This means that the heat transfer from the working gases to the cylinder walls is mainly driven by the incylinder gas motion and the gas properties of the fluid. The convective heat transfer can be expressed through the convection coefficient (h) if the heat transfer is assumed to be quasi-steady. This coefficient can be calculated using Equation (1). (1)Where q is the measured heat flux, T w the measured wall temperature and T g the gas temperature. The wall temperature and the heat flux are measured and calculated using thin film Resistance Temperature Detectors (RTDs). These heat flux sensors have also been used in [1,3,4,5].The heat transfer models used in current engine simulation software are mostly based on the models of Annand [6] or Woschni [7]. These models have been developed for a one-zone combustion model. This means the gas temperature is a bulk averaged value. The use of a bulk value implies that the ef...

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“…An overview of the discussed measurements is given in Table 1. [18,19] are much higher because the intake air was preheated up to 320 • C to have the same initial conditions that enable HCCI combustion in their engine. Consequently, it is impossible to quantitatively compare their results with those of the others.…”

Section: Measurements Under Motored Conditionsmentioning

confidence: 99%

“…Overbye et al [20] and Boggs and Borman [18,19] used coaxial sensors to measure the heat transfer inside a CFR (Cooperative Fuel Research) engine with a shrouded intake valve, varying the shroud position to produce different flows and levels of turbulence. They found that the heat flux was higher for each other are strongly correlated.…”

Section: Influence Of Intake Flowmentioning

confidence: 99%

Heat transfer in premixed spark ignition engines part I: Identification of the factors influencing heat transfer

Broekaert

Demuynck

Cuyper

et al. 2016

Energy

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The heat transfer from the combustion gases to the cylinder walls inside a spark ignition engine is a key factor in an engine's design, due to its influence on the engine's efficiency, power and emissions. Therefore a lot of research has been conducted in order to accurately model the heat transfer, for engine design and optimization purposes. These models have been found to provide inaccurate predictions for fuels which have significantly different gas properties compared to traditional fossil fuels. This indicates that the models either do not properly include gas properties, or are missing some important properties in their formulation. In order to construct a general ("fuel-independent") heat transfer model, new measurements need to be executed, with multiple fuels that have different properties. Designing such an experiment requires a thorough understanding of the factors influencing the heat transfer and their interactions. In this paper a literature review is presented of heat transfer measurements in spark ignition engines in order to investigate the effect of the engine factors on the heat transfer. Based on this review, a root cause analysis is conducted to identify the independent factors that affect heat transfer. These factors are then used to set up two experiments according to a Design of Experiments methodology that allows the investigation of the effect of different gas properties and engine settings on the heat transfer in a consistent way. The results of these measurements for motored operation are discussed in [1] and for fired operation in a companion paper [2].

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Calculation of Heat Flux Integral Length Scales from Spatially-Resolved Surface Temperature Measurements in an Engine

Cited by 11 publications

References 23 publications

The Influence of Thermal Barrier Coating Surface Roughness on Spark-Ignition Engine Performance and Emissions

The Influence of Thermal Barrier Coating Surface Roughness on Spark-Ignition Engine Performance and Emissions

Studying the Effect of the Flame Passage on the Convective Heat Transfer in a S.I. Engine

Heat transfer in premixed spark ignition engines part I: Identification of the factors influencing heat transfer

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