Heat transfer in exhaust system of a cold start engine at low environmental temperature

Petkovic, D Snezana; Pešić, Radivoje; Lukic, K Jovanka

doi:10.2298/tsci100505070p

Cited by 4 publications

(6 citation statements)

References 2 publications

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“…In the study of heat transfer of an SCR catalyst, a circular microchannel geometry was adopted. In the case of an SCR catalyst, heat transfer takes place between the walls of the microchannels and the AdBlue vapours that are found diffused in the exhaust gas through several mechanisms [18], as shown in Figure 3. The role of AdBlue injection is to disperse the solution in micrometre-sized aerosols in order to achieve a more uniform distribution in the exhaust gas, which contributes to improving the efficiency of the catalytic reduction process [9].…”

Section: Heat Exchange In Microchannels and Other Scr Componentsmentioning

confidence: 99%

“…In a first step, the conditions under which the desublimation process occurs as a function of the change in exhaust gas temperature and temperature evolution in certain SCR components were investigated. Literature such as [ 11 , 13 , 18 ] investigated different geometries and heat transfer aspects in such systems. In the study of heat transfer of an SCR catalyst, a circular microchannel geometry was adopted.…”

Section: Heat Exchange In Microchannels and Other Scr Componentsmentioning

confidence: 99%

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Pseudo-Desublimation of AdBlue Microdroplets through Selective Catalytic Reduction System Microchannels and Surfaces

Picus,

Mihai,

Suciu

2023

Micromachines

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In the present paper, the occurrence and development of the pseudo-desublimation process of AdBlue microdroplets in the microchannels and surfaces of catalytic reduction systems (SCR) are reported. In order to understand how the pseudo-desublimation process develops, the influence of heat flux values on the heat transfer of AdBlue injection was analysed, taking into account the structure of the microchannels inside the SCR and the overall configuration of the installation. The evolution of the AdBlue vapour flow in the SCR system was simulated, as well as the temperature variation along an SCR microchannel through which the mixture flows. An experimental set-up was designed in order to visualise and interpret the processes at the onset of pseudo-desublimation. The results described in this paper confirm the existence of a pseudo-desublimation process that occurs only under certain temperature conditions when AdBlue is injected into SCR systems. The characteristics of the crystals formed and their growth rate depend on the working temperature, which could be controlled by efficient preheating methods immediately after engine start. A better understanding of the process will allow the development of methods of avoiding solid depositions on SCR system components, which has a direct impact on SCR catalyst performance and durability.

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Section: Heat Exchange In Microchannels and Other Scr Componentsmentioning

confidence: 99%

Section: Heat Exchange In Microchannels and Other Scr Componentsmentioning

confidence: 99%

Pseudo-Desublimation of AdBlue Microdroplets through Selective Catalytic Reduction System Microchannels and Surfaces

Picus,

Mihai,

Suciu

2023

Micromachines

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“…Detailed description of the model can be found in the papers [6,7]. Detailed description of the model can be found in the papers [6,7].…”

Section: Mathematical Modelmentioning

confidence: 99%

Experimental verification of mathematical model of the heat transfer in exhaust system

Petkovic¹,

Pešić²,

Lukić³

2011

THERM SCI

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A Catalyst convertor has maximal efficiency when it reaches working temperature. In a cold start phase efficiency of the catalyst is low and exhaust emissions have high level of air pollutants. The exhaust system optimization, in order to decrease time of achievement of the catalyst working temperature, caused reduction of the total vehicle emission. Implementation of mathematical models in development of exhaust systems decrease total costs and reduce time. Mathematical model has to be experimentally verified and calibrated, in order to be useful in the optimization process. Measurement installations have been developed and used for verification of the mathematical model of unsteady heat transfer in exhaust systems. Comparisons between experimental results and the mathematical model are presented in this paper. Based on obtained results, it can be concluded that there is a good agreement between the model and the experimental results

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“…In order to reduce emission during the cold start phase, various solutions can be implemented in both the engine and exhaust system, such as a faster catalytic converter action to increase the efficiency of exhaust gas processing. Among all the techniques proposed in the past few years, as demonstrated by the work of Petković et al [1], passive systems are being widely investigated. They include a simple constructional alteration on the exhaust manifold, which can be used to reduce heat losses to the atmosphere.…”

Section: Introductionmentioning

confidence: 99%

Heat Transfer Investigation in an Engine ExhaustType Pulsating Flow

Simonetti¹,

Caillol²,

Higelin³

et al. 2018

JFFHMT

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In many practical engineering situations, such as in the exhaust pipes of Internal Combustion Engines, heat is transferred under conditions of pulsating flow. In these conditions, the heat transfer mechanism is affected by the pulsating flow parameters. The objective of the present work was to experimentally investigate heat transfers for pulsatile turbulent flows in a pipe. A specific experimental apparatus able to reproduce a pulsating flow representative of the engine exhaust was designed. A stationary turbulent hot air flow with a Reynolds number ranging from 1.8x10 4 to 3.5x10 4 , based on the time averaged velocity, is excited through a pulsating mechanism and exchanges thermal energy with a steel pipe. Pulsation frequency ranges from 10 to 95 Hz. The effects of pulsation frequency and pipe length on the convective heat transfer were evaluated. It was observed that flow pulsation enhances convective heat transfers in comparison with the steady case. The results highlight that, when the flow is excited with a pulsation frequency equal to a resonance mode of the system, a local maximum of the heat transfer rate appears. This behaviour was found to be independent of the pipe length. Instantaneous measurements of air velocity and temperature demonstrated that the increase in the energy axial advection due to the oscillating component of the velocity is the major cause of the heat transfer enhancement.

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Heat transfer in exhaust system of a cold start engine at low environmental temperature

Cited by 4 publications

References 2 publications

Pseudo-Desublimation of AdBlue Microdroplets through Selective Catalytic Reduction System Microchannels and Surfaces

Pseudo-Desublimation of AdBlue Microdroplets through Selective Catalytic Reduction System Microchannels and Surfaces

Experimental verification of mathematical model of the heat transfer in exhaust system

Heat Transfer Investigation in an Engine ExhaustType Pulsating Flow

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