15 research outputs found
External heat losses in small turbochargers: Model and experiments
[EN] The behavior of small turbochargers is deeply affected by heat transfer phenomena. The external heat losses of these machines are studied and a simplified model that takes into account both radiation and convective mechanisms has been proposed. The model has been adjusted in a turbocharger test bench for two different turbochargers, later on it has been validated against experimental measurements on an engine test bench. Finally, the model has been used to estimate the most important external heat flows among the different elements of the turbocharger, showing the operative points in which external heat transfer in turbochargers cannot be neglected. (C) 2014 Elsevier Ltd. All rights reserved.This work has been financial supported by Jaguar Land Rover Ltd.Payri González, F.; Olmeda, P.; Arnau Martínez, FJ.; Dombrovsky, A.; Smith, L. (2014). External heat losses in small turbochargers: Model and experiments. Energy. 71:534-546. https://doi.org/10.1016/j.energy.2014.04.096S5345467
A study on the internal convection in small turbochargers. Proposal of heat transfer convective coefficients
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 temperatures (compressor, turbine, oil and coolant).
The former is needed to feed accurately ICE model, turbine outlet temperature is important for aftertreatment
device modelling while oil and coolant temperatures are important in order to design optimum
cooling systems.This work has been partially supported by the Spanish Ministerio de Economa y Competitividad through grant no. TRA2012-36954. The equipment used in this work has been partially supported by FEDER project funds "Dotacion de infraestructuras cientifico tecnicas para el Centro Integral de Mejora Energetica y Medioambiental de Sistemas de Transporte (CiMeT), (FEDER-ICTS-2012-06)", framed in the operational program of unique scientific and technical infrastructure of the Ministry of Science and Innovation of Spain.Serrano Cruz, JR.; Olmeda González, PC.; Arnau Martínez, FJ.; Reyes Belmonte, MÁ.; Tartoussi, H. (2015). A study on the internal convection in small turbochargers. Proposal of heat transfer convective coefficients. Applied Thermal Engineering. 89:587-599. https://doi.org/10.1016/j.applthermaleng.2015.06.053S5875998