A Rational Approach for Calculation of Heat Transfer in Diesel Engines

Sitkei, György; Ramanaiah, G.

doi:10.4271/720027

Cited by 57 publications

(37 citation statements)

References 5 publications

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“…A wealth of literature has been published over the years regarding the gas-to-wall heat transfer process in SI and CI engines and a number of correlations have been proposed for calculating the instantaneous heat transfer coefficient [6][7][8][9][10][11][12][13][14][15]. These studies have generally relied on dimensional analysis for turbulent flow that correlates the Nusselt, Reynolds, and Prandtl numbers.…”

Section: Introductionmentioning

confidence: 99%

New Heat Transfer Correlation for an HCCI Engine Derived from Measurements of Instantaneous Surface Heat Flux

Chang

Güralp

Filipi

et al. 2004

SAE Technical Paper Series

402

244

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An experimental study has been carried out to provide qualitative and quantitative insight into gas to wall heat transfer in a gasoline fueled Homogeneous Charge Compression Ignition (HCCI) engine. Fast response thermocouples are embedded in the piston top and cylinder head surface to measure instantaneous wall temperature and heat flux. Heat flux measurements obtained at multiple locations show small spatial variations, thus confirming relative uniformity of incylinder conditions in a HCCI engine operating with premixed charge. Consequently, the spatially-averaged heat flux represents well the global heat transfer from the gas to the combustion chamber walls in the premixed HCCI engine, as confirmed through the gross heat release analysis. Heat flux measurements were used for assessing several existing heat transfer correlations. One of the most popular models, the Woschni expression, was shown to be inadequate for the HCCI engine. The problem is traced back to the flame propagation term which is not appropriate for the HCCI combustion. Subsequently, a modified model is proposed which significantly improves the prediction of heat transfer in a gasoline HCCI engine and shows very good agreement over a range of conditions.

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Section: Introductionmentioning

confidence: 99%

New Heat Transfer Correlation for an HCCI Engine Derived from Measurements of Instantaneous Surface Heat Flux

Chang

Güralp

Filipi

et al. 2004

SAE Technical Paper Series

402

244

View full text Add to dashboard Cite

show abstract

“…As in most correlations, the constant a in equations (7) and (9) is a scaling factor, which is believed to depend on engine type, but also on the particular operating condition. A value of 0.0947 was found appropriate to match the cycle-averaged heat transfer coefficient predicted by equation (9) with the experimental steady-state coefficient obtained in the test engine at the condition near maximum power (4000 r/min and 100 per cent of the limiting torque).…”

Section: Proposal For a Modified Heat Transfer Correlationmentioning

confidence: 99%

“…For this reason, in the cases of the correlations proposed by Annand [5] and Sitkei and Ramanaiah [7], the radiative part of the coefficient was calculated using the steady-state mean cylinder head temperature obtained from the experiments.…”

Section: Introductionmentioning

confidence: 99%

Thermal modelling of modern diesel engines: proposal of a new heat transfer coefficient correlation

Finol

Robinson

2011

Proceedings of the Institution of Mechanical Engineers, Part D:

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Existing methods for predicting heat fluxes and temperatures in internal combustion engines, which take the form of correlations to estimate the heat transfer coefficient on the gas-side of the combustion chamber, are based on methodology developed over the past 50 years, often updated in view of more recent experimental data. The application of these methods to modern diesels engines is questionable because key technologies found in current engines did not exist or were not widely used when those methods were developed. Examples of such technologies include: high-pressure common rail and variable fuel injection strategies including retarded injection for nitrogen oxides emission control; exhaust gas re-circulation; high levels of intake boost pressure provided by a single-or double-stage turbocharger and inter-cooling; multiple valves per cylinder and lower swirl; and advanced engine management systems. This suggests a need for improved predicting tools of thermal conditions, specifically temperature and heat flux profiles in the engine block and cylinder head. In this paper a modified correlation to predict the gas-side heat transfer coefficient in diesel engines is presented. The equation proposed is a simple relationship between Nu and Re calibrated to predict the instantaneous spatially averaged heat transfer coefficient at several operating conditions using air as gas in the model. It was derived from the analysis of experimental data obtained in a modern diesel engine and is supported by a research methodology comprising the application of thermodynamic principles and fundamental equations of heat transfer. The results showed that the new correlation adequately predicted the instantaneous coefficient throughout the operating cycle of a high-speed diesel engine. It also estimated the corresponding cycleaveraged heat transfer coefficient within 10 per cent of the experimental value for the operating conditions considered in the analysis.

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“…This demonstrates that it is better to calculate the gas properties instead of using assump-375 tions which are only valid for air, especially when dealing with hydrogen. This seems obvious, but it has been overlooked by many authors who build upon the model of Woschni for fossil fuels [26,27,28] or hydrogen [29].…”

Section: Fired Operation -Hydrogenmentioning

confidence: 99%

On the applicability of empirical heat transfer models for hydrogen combustion engines

Demuynck

Paepe

Huisseune

et al. 2011

International Journal of Hydrogen Energy

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On the applicability of empirical heat transfer models for hydrogen combustion engines AbstractHydrogen-fuelled internal combustion engines are being investigated as an alternative for current drive trains because they have a high efficiency, near-zero noxious and zero tailpipe greenhouse gas emissions. A thermodynamic model of the engine cycle would enable a cheap and fast optimization of engine settings for operation on 10 hydrogen, facilitating the development of these engines. The accuracy of the heat transfer submodel within the thermodynamic model is important to simulate accurately the emissions of oxides of nitrogen which are influenced by the maximum gas temperature. These emissions can occur in hydrogen internal combustion engines at high loads and they are an important constraint for power and efficiency optimization. The most 15 common heat transfer models in engine research are those from Annand and Woschni. These models are developed for fossil fuels, which have different combustion properties. Therefore, they need to be evaluated for hydrogen. We have measured the heat flux and the wall temperature in an engine that can run on hydrogen and methane. This paper describes an evaluation of the models of Annand and Woschni, using those heat 20 flux measurements and assesses if the models capture the effect of changing combustion and fuel properties. The models fail on all the tests, so they need to be improved to accurately model the heat transfer generated by hydrogen combustion.Keywords: hydrogen, methane, internal combustion engine, experimental, heat transfer, model

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A Rational Approach for Calculation of Heat Transfer in Diesel Engines

Cited by 57 publications

References 5 publications

New Heat Transfer Correlation for an HCCI Engine Derived from Measurements of Instantaneous Surface Heat Flux

New Heat Transfer Correlation for an HCCI Engine Derived from Measurements of Instantaneous Surface Heat Flux

Thermal modelling of modern diesel engines: proposal of a new heat transfer coefficient correlation

On the applicability of empirical heat transfer models for hydrogen combustion engines

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