General Procedure for the Determination of Heat Transfer Properties in Small Automotive Turbochargers

Serrano, José Ramón; Olmeda, Pablo; Arnau, Francisco José; Dombrovsky, Artem

doi:10.4271/2014-01-2857

Cited by 22 publications

(32 citation statements)

References 24 publications

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“…A hypothesis of mean temperature for oil is done according to the temperature values calculated previously in order to maintain the lubrication of turbocharger under safe conditions. The convective conductance between the oil and H2 metal node needs to be calculated through dimensionless numbers of Reynolds, Prandtl, Nusselt and additional external geometry using proposed correlations [27] . The convective heat transfer coefficient for the oil and water can be obtained with equation 3, where k is the conductivity of the fluid and D refers to the diameter of the inlet port.…”

Section: Modelling Results and Discussionmentioning

confidence: 99%

“…Finally equation (4) represents the integral of the heat flow already calculated, which can be used to estimate the acting time for the auxiliary pump system. C is the sum of all capacitances of the five metal nodes of the turbocharger thermal, obtained experimentally [27,29], and ∆ is the temperature decrease from an initial case simulated that lack of any type of extra cooling after the hot-stop. ∫̇ = ⋅ ∆…”

Section: Modelling Results and Discussionmentioning

confidence: 99%

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Adaptation of a 1-D tool to study transient thermal in turbocharger bearing housing

Serrano

Tiseira

Usaquén

2018

Applied Thermal Engineering

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The heat transfer model can be used in a one-dimensional (1-D) engine simulation. When the engine speed is reduced to zero, the codes have been upgraded to calculate transient turbocharger thermal conditions. The turbocharger model has been used as an external plugin. Analysis of the temperature evolution at different parts of the turbocharger is done by using a hot spot engine cycle. A turbocharger bypassing strategy is done by means of a 9 bypass valve system. By using this method, instabilities can be found in the binary onoff state of an engine. Highlights  Thermal sensitivity is measured in the turbocharger in regards to a onedimensional engine.  A visual aid, such as a model, can help depict the evolution of thermal theory.  The behaviour of a turbocharger in a hot stop is affected by such diverse cooling strategies.  A coke phenomenon in the lubricating circuit affects turbocharger efficiency and durability.  High temperatures that occur within a turbocharger produce problems such as clogged bearing systems and damaged shafts.

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Section: Modelling Results and Discussionmentioning

confidence: 99%

Section: Modelling Results and Discussionmentioning

confidence: 99%

Adaptation of a 1-D tool to study transient thermal in turbocharger bearing housing

Serrano

Tiseira

Usaquén

2018

Applied Thermal Engineering

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“…The actual mass flow through waste-gate and by-pass valves is calculated as the difference between the measured mass flow through both turbines and 64 3.3. Gas stand 6. This is possible due to the availability of manufacturers maps of both the HPT and the LPT.ṁ…”

Section: By-pass and Waste-gate Valves Flow Characterisationmentioning

confidence: 99%

“…The final appearance of an instrumented turbocharger with wall thermocouples is shown in Figure 3. 6. It can be observed that different axial sections have been chosen in which three thermocouples for each section have been installed.…”

Section: Heat Transfer Characterization Testsmentioning

confidence: 99%

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Synthesis of the 1D modelling of turbochargers and its effects on engine performance prediction

Dombrovsky¹

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Low fuel consumption is one of the main requirement for current internal combustion engines for passenger car applications. One of the most used strategies to achieve this goal is to use downsized engines (smaller engines while maintaining power) what implies the usage of turbochargers. The coupling between both machines (the turbocharger and the internal combustion engines) presents many difficulties due to the different nature between turbomachines and reciprocating machines. These difficulties make the optimal design of the turbocharged internal combustion engines a complicated issue.In these thesis a strong effort has been made to improve the global understanding of different physical phenomena occurring in turbochargers and in turbocharged engines. The work has been focused on the 1D modelling of the phenomena since 1D tools currently play a major role in the engine design process. Both experimental and modelling efforts have been made to understand the heat transfer and gas flow processes in turbochargers. Previously to the experimental analysis a literature review has been made in which the state of the art of heat transfer and gas flow modelling in turbochargers have been analysed.The experimental effort of the thesis has been focused on measuring different turbochargers in the gas stand and the engine test bench. In the first case, the gas stand, a more controlled environment, has been used to perform tests at different conditions. Hot tests with insulated and not insulated turbocharger have been made to characterise the external heat transfer. Moreover, adiabatic tests have been made to compare the effect of the heat transfer on different turbocharger variables and for the validation of the turbine gas flow models. In the engine test bench full and partial load tests have been made for model validation purposes.For the models development task, the work has been divided in heat flow models and gas flow models. In the first case, a general heat transfer model for turbochargers has been proposed based on the measured turbochargers and data available from previous works of the literature. This model includes a procedure of conductive conductances estimation, internal and external convection correlations and radiation estimation procedure. In the case of the gas flow modelling, an extended model for VGT performance maps extrapolation for both the efficiency and the mass flow has been developed as well as a model for discharge coefficient prediction in valves for two stage turbochargers.Finally, the models have been fully validated coupling them with a 1D modelling software simulating both the gas stand and the whole engine. On the one hand, the results of the validation show that compressor and turbine outlet temperature prediction is highly improved using the developed models. This results prove that the turbocharger heat transfer phenomena are important not only for partial load and transient simulation but also in full loads. On the other hand, the VGT extrapolation model accuracy is high even at...

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A study on the internal convection in small turbochargers. Proposal of heat transfer convective coefficients

Serrano

Olmeda

Arnau

et al. 2015

Applied Thermal Engineering

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Nowadays turbochargers play an important role in improving internal combustion engines (ICE) performance. Usually, engine manufacturers use computer codes to predict the behaviour of both engine and turbocharger, the later by means of measured look-up maps. Using look-up maps different problems arise, being one of the most important the difference in heat transfer between the current operating condition and the conditions at which maps were measured. These effects are very important at low to medium turbocharger speeds (typical condition of urban driving conditions) where heat transfer can even be higher than mechanical power. In this work, the different convective heat transfer phenomena inside these kind of machines have been measured and analysed.Besides, general correlations for these flows, based on dimensionless numbers, are fitted and validated in three different turbochargers. The applicability of the model is shown by comparison the main results obtained when the model is used and not , improving up to 20• C the predicted turbine outlet temperature. The main advantages of applying these correlations rely on predicting fluids outlet

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General Procedure for the Determination of Heat Transfer Properties in Small Automotive Turbochargers

Cited by 22 publications

References 24 publications

Adaptation of a 1-D tool to study transient thermal in turbocharger bearing housing

Adaptation of a 1-D tool to study transient thermal in turbocharger bearing housing

Synthesis of the 1D modelling of turbochargers and its effects on engine performance prediction

A study on the internal convection in small turbochargers. Proposal of heat transfer convective coefficients

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