Experimental verification of hydrodynamic similarity in hot flows

Torregrosa, A.J.; Broatch, A.; García-Tíscar, J.; Roig, Ferran

doi:10.1016/j.expthermflusci.2020.110220

Cited by 8 publications

(10 citation statements)

References 12 publications

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“…In both cases, the dependence of pressure drop on the mass flow is essentially quadratic, but with a non-negligible linear contribution, associated with the existence of laminar flow in the TWC and, most notably, across the wallflow filter. 36 The modeling work was performed with GT-Power, that was used to emulate in full the experimental procedure. Both the TWC and the GPF were modeled, The basic approach consisted in tuning the model parameters so that the best possible reproduction of the results of the experiments in ''new'' condition was achieved, and then introduce a physically meaningful modification so that the results of the experiments in ''used'' conditions might also be reproduced.…”

Section: Results: Pressure Dropmentioning

confidence: 99%

Section: Results: Pressure Dropmentioning

confidence: 99%

“…In the steady flow configuration, the total pressure drop across the ATS was measured as a function of the mass flow rate for mass flows up to 0.22 kg/s and in cold conditions (ambient temperature) as, even if the temperatures in the real exhaust are considerable, it has been demonstrated 36 that cold flow results may be soundly extrapolated to hot conditions. The experimental procedure is summarized in the following (full details can be found elsewhere 37 ).…”

Section: Assessment Of Reactive and Dissipative Effectsmentioning

confidence: 99%

See 2 more Smart Citations

A study of the early life of gasoline particulate filters: Reactive and dissipative acoustic effects

Torregrosa

Morena

Sanchis

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part D:

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The presence of after-treatment systems (ATS) has some side effects as they modify the wave dynamics, back-pressure and acoustic behavior of the exhaust system, that define the boundary conditions for the main silencing device. Gasoline particulate filters (GPF) have a considerable influence on these traits as their working principle depends on wall-flow monoliths; additionally, particulate filters have an inherent transient behavior due to the loading-regeneration cycles during their operation. In this paper, the steady and unsteady behavior of a typical device containing a three-way catalyst (TWC) and a GPF has been characterized in "new" (prior to any use) and "used" (after regeneration) conditions, with special focus on the role of dissipation. Pressure drop measurements were used in steady flow, whereas an acoustic energy balance was performed in the unsteady case that allows for the identification of the reactive and dissipative contributions. The results obtained for the GPF suggest that after it has been used for a relatively short time it oscillates between a maximum and a minimum loading over load–regeneration cycles burning the soot, never reaching back brand–new cleanness due to accumulation into the substrate pores and only suffering from ash accumulation over very long times. The results were then used to analyze the ability of a standard gas-dynamic code to reproduce the influence of the loading on the reactive and dissipative effects observed, with the main conclusion that by properly tuning the model parameters it is possible to reproduce, at least qualitatively, the trends observed in the experiments. The model can thus be used to provide adequate inlet conditions for the design of the exhaust line.

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Section: Results: Pressure Dropmentioning

confidence: 99%

Section: Results: Pressure Dropmentioning

confidence: 99%

Section: Assessment Of Reactive and Dissipative Effectsmentioning

confidence: 99%

See 1 more Smart Citation

A study of the early life of gasoline particulate filters: Reactive and dissipative acoustic effects

Torregrosa

Morena

Sanchis

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part D:

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“…The High Mass-flow and High Temperature (HMHT) flow bench, installed in the 8P laboratory of UPV, is a multipurpose experimental facility for aerodynamic studies in both automotive [13][14][15] and aeronautical engineering [16], as it provides a fairly large flow rate, more than 2 kg/s cold flow and hot flows at temperatures that can reach 1000ºC with 1 kg/s flow rates. This facility is powered by a 500 kW two-stage centrifugal compressor in series with a 1 MW Diesel combustor.…”

Section: B Experimental Setupmentioning

confidence: 99%

Numerical and experimental analysis of thermo-aerodynamic performance in an aero engine surface heat exchanger

Chávez-Módena

Valero

González

et al. 2021

Aiaa Aviation 2021 Forum

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A surface air-cooled oil cooler (SACOC) is a passive heat exchanger used to evacuate a large quantity of heat from the oil circuit of a turbofan engine to its secondary flow with minimal perturbation. Using the secondary flow as a heat sink has the advantage of the evacuated enthalpy being available in the nozzle. The performance of a SACOC is therefore measured in terms of maximum heat release capacity with minimal pressure loss and flow perturbations.These heat exchangers are typically composed of parallel fins and are usually tested in bespoke wind tunnels where the interaction between the three-dimensional high velocity flow and the heat exchangers is evaluated. Modern numerical computations that include the solution of the fluid equations in the flow field and a conjugate thermal problem can be also performed. This numerical approach, once validated, allows a complete and computationally affordable analysis of the aero-thermodynamic performance of the SACOC. In this work, a first comparison between both experimental and computational perspectives is presented in terms of pressure and temperature profiles to achieve a complete characterization of the device. This double experimental numerical perspective allows comparing the behaviour of the different fins of the SACOC depending on their relative position but also to trust the numerical conclusions with experimental robust data.

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“…While this does not pose any significant problem in the case of the silencers, that operate at moderately high temperatures, in the case of the aftertreatment systems, that operate at the highest temperatures in the exhaust line, some doubts may arise. In fact, it was recently proven that, in the case of aftertreatment systems, the pressure drop does not follow in full the expected similarity as a function of the Reynolds number, and the differences could not be explained on the single basis of compressibility effects [25]. Therefore, it is interesting to dispose of some assessment of the actual performance of extrapolating the results of acoustic measurements at room temperature to hot-flow conditions.…”

Section: Introductionmentioning

confidence: 99%

On the Applicability of Cold Acoustic Measurements to High-Amplitude Hot Pulsating Flows

et al. 2022

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The experimental characterization of the acoustic characteristics of engine exhaust devices is usually carried out through measurements in cold conditions, due to the intrinsic difficulties associated with proper temperature control in an acoustic rig. While those measurements may be sufficiently indicative for the cold end of the exhaust (the silencing elements) their significance for the hot end (the aftertreatment system) is more doubtful, as a result of the high temperatures and, eventually, the higher amplitude of pressure waves acting on the system. In this paper, a direct assessment is provided on the significance of acoustic measurements in cold conditions for representing the actual behaviour of an aftertreatment system in a hot pulsating, engine-like flow. Making use of wave decomposition techniques, the measured characterization was convoluted with the hot-flow excitation and the device responses were directly compared. The results indicate that, while it is not possible to fully reproduce the behaviour observed in hot pulsating flow, the tendencies are reproduced, at least qualitatively. In particular, the effect of soot loading is fairly reproduced.

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Experimental verification of hydrodynamic similarity in hot flows

Cited by 8 publications

References 12 publications

A study of the early life of gasoline particulate filters: Reactive and dissipative acoustic effects

A study of the early life of gasoline particulate filters: Reactive and dissipative acoustic effects

Numerical and experimental analysis of thermo-aerodynamic performance in an aero engine surface heat exchanger

On the Applicability of Cold Acoustic Measurements to High-Amplitude Hot Pulsating Flows

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