Evaluation of heat transfer effects in small turbochargers by theoretical model and its experimental validation

Marelli, Silvia; Marmorato, Giulio; Capobianco, Massimo

doi:10.1016/j.energy.2016.06.067

Cited by 35 publications

(27 citation statements)

References 12 publications

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“…The experimental performance maps have been measured at the turbocharger test facility of the University of Genoa (Fig. 1), fully described in a previous paper [16]. The test facility is especially suited to test turbochargers thanks to the availability of two independent feeding line for both turbine and compressor.…”

Section: Experimental Activitymentioning

confidence: 99%

“…Pulse generators [17] could be used to replicate the turbocharger behaviour under unsteady flow typically occurring in intake and exhaust engine circuits. Static pressure is measured through strain gauge transducers (with an accuracy of 0.15% of the full scale) placed upstream and downstream of the compressor and the turbine, a high frequency response piezoresistive pressure transducer is installed downstream of the compressor, to detect surge phenomena [16,18]. Total temperatures are measured through platinum resistance thermometers (with an accuracy of ±0.15 °C ± 0.2% of measured value) and thermocouples.…”

Section: Experimental Activitymentioning

confidence: 99%

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Energy Harvesting Technology for turbocompounding automotive engines with waste-gate valve

et al. 2019

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The reduction of CO2 and, more generally, GHG (Green House Gases) emissions imposed by the European Commission (EC) and the Environmental Protection Agency (EPA) for passenger cars has driven the automotive industry to develop technological solutions to limit exhaust emissions and fuel consumption, without compromising vehicle performance and drivability. In a mid-term scenario, hybrid powertrain and Internal Combustion Engine (ICE) downsizing represent the present trend in vehicle technology to reduce fuel consumption and CO2 emissions. Concerning downsizing concept, to maintain a reasonable power level in small engines, the application of turbocharging is mandatory for both Spark Ignition (SI) and Diesel engines. Following this aspect, the possibility to recover the residual energy of the exhaust gases is becoming more and more attractive, as demonstrated by several studies around the world. One method to recover exhaust gas energy from ICEs is the adoption of turbo-compounding technology to recover sensible energy left in the exhaust gas by-passed through the waste-gate valve. In the paper, an innovative option of advanced boosting system is investigated through a bladeless micro expander, promising attractive cost-competitiveness. The numerical activity was developed on the basis of experimental data measured on a waste-gated turbocharger for downsized SI automotive engines. To this aim, mass flow rate through the by-pass valve and the turbine impeller was measured for different waste-gate settings in steady-state conditions at the turbocharger test bench of the University of Genoa. The paper shows that significant electrical power can be harvested from the waste-gate gases, up to 94 % of compressor power, contributing to fuel consumption reduction.

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Section: Experimental Activitymentioning

confidence: 99%

Section: Experimental Activitymentioning

confidence: 99%

Energy Harvesting Technology for turbocompounding automotive engines with waste-gate valve

et al. 2019

Self Cite

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show abstract

“…Dedicated investigations on the turbocharging system are therefore necessary to achieve a better understanding of its performance, particularly in unsteady flow conditions typically occurring in the intake and exhaust systems of internal combustion engines. One-dimensional models, generally adopted to compute the engine-turbocharger matching, require several information on turbine and compressor behavior [4,5,6] when quasi-steady approaches, based on compressor and turbine characteristic maps, are adopted. In many cases, a limited range of operating conditions of the turbocharger device is available, and mathematical techniques for the extrapolation of maps are commonly utilized.…”

Section: Introductionmentioning

confidence: 99%

“…If the heat transfer effect from the hot side (turbine and intermediate casing) to the cold side (compressor) is taken into account [6,9,10,11], a good accuracy in the compressor efficiency evaluation can be achieved.…”

Section: Introductionmentioning

confidence: 99%

Direct Evaluation of Turbine Isentropic Efficiency in Turbochargers: CFD Assisted Design of an Innovative Measuring Technique

Marelli¹,

Usai²,

Capobianco³

et al. 2019

SAE Technical Paper Series

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Turbocharging is playing today a fundamental role not only to improve automotive engine performance, but also to reduce fuel consumption and exhaust emissions for both Spark Ignition and Diesel engines. Dedicated experimental investigations on turbochargers are therefore necessary to assess a better understanding of its performance. The availability of experimental information on turbocharger steady flow performance is an essential requirement to optimize the engine-turbocharger matching, which is usually achieved by means of simulation models. This aspect is even more important when referred to the turbine efficiency, since its swallowing capacity can be accurately evaluated through the measurement of mass flow rate, inlet temperature and pressure ratio across the machine. However, in the case of a turbocharger radial inflow turbine, isentropic efficiency, directly evaluated starting from measurement of thermodynamic parameters at the inlet and outlet sections, can give significant errors. This inaccuracy is mainly related to the difficulty of a correct evaluation of the turbine outlet temperature due to the non-uniform distribution of flow field and temperature at the measuring section. This work is the follow up of a previous publication where an intensive measurement campaign was performed to obtain a reliable measurement of the turbine outlet temperature. To this aim, a handmade 3-hole probe (unlike most of the measuring probes available on the market, which are considered as intrusive) was adopted to perform measurement of the flow field, pressure and temperature downstream the turbine with special reference to different radial and tangential positions in two sections located near and far from the outlet machine, allowing the evaluation of the efficiency through local enthalpy fluxes across the turbine in cold and hot conditions upstream the turbine. The comparison between results obtained through the local measurements and those achieved through a direct measurement of turbine outlet temperature by three probes inserted in pipe with a different protrusion, have highlighted that heat transfer effects across the pipes and across the turbocharger components play an important role on the estimation of temperature profile at the outlet section. In order to put some light on this aspect, CFD simulations have been performed to estimate the impact of the heat transfer and flow distribution on the estimation of the isentropic efficiency. The OpenFOAM ® code has been adopted to simulate the actual turbine geometry resorting to multi reference frame (MRF) strategies, instead of mesh motion strategies, to characterize the flow pattern downstream of the turbine. Moreover, CFD analysis was used to design a specific device, whose goal was the dissipation of flow structures dominated by vorticity, achieving in this way a uniform distribution of the flow and temperature fields at the measuring section. This will result in a much more reliable evaluation of the turbine efficiency

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“…[62] Heat transfer effect was evaluated with an intention to improve compressor efficiency. This method seems to be advantageous in terms of database economy, requirement of fewer geometrical and physical attributes and there is no need of a local test bench for achieving compressor maps.…”

Section: Thermal Performance and Heat Balance Of Turbochargermentioning

confidence: 99%

Efficiency of Nano Ceramic Coated and Turbocharged Internal Combustion Engine- A Review

Diaz¹

2017

JAMES

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Thermal Barrier Coating (TBC) often denotes the ceramic/Nano ceramic insulation layered to the surface of the engine or any other parts to enhance the thermal insulation characteristics by increasing efficiency and minimizing the need of cooling system. Above all, load and speed of the engine is optimized with respect to output power, volumetric efficiency and exhaust control. Insulation of combustion chamber with ceramic enhances its efficiency and it is also significant in terms of pollution control and fatigue lifespan. On account of these, this article reviews a list of papers that contribute in studies, where the influence of nano ceramic coating and the use of turbocharging mechanism in optimization of engine performance are described.

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Evaluation of heat transfer effects in small turbochargers by theoretical model and its experimental validation

Cited by 35 publications

References 12 publications

Energy Harvesting Technology for turbocompounding automotive engines with waste-gate valve

Energy Harvesting Technology for turbocompounding automotive engines with waste-gate valve

Direct Evaluation of Turbine Isentropic Efficiency in Turbochargers: CFD Assisted Design of an Innovative Measuring Technique

Efficiency of Nano Ceramic Coated and Turbocharged Internal Combustion Engine- A Review

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