Heat transfer enhancement in the oscillating turbulent flow of a pulse combustor tail pipe

Dec, John E.; Keller, Jay O.; Arpacı, Vedat S.

doi:10.1016/0017-9310(92)90074-3

Cited by 69 publications

(27 citation statements)

References 15 publications

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“…It is obvious that the distortion of the cyclic temperature curves deviated from the sinusoidal fluctuation damps with the increase in the Womersley number. Similar cyclic centerline velocity and temperature pulsations were found in experimental results of turbulent pulsating channel flow with large velocity oscillating amplitudes by Dec et al [20,47,48].…”

Section: The Effect Of Temperature Oscillation At Inletsupporting

confidence: 84%

“…(16) loses its physical meaning. In this case, the section-average temperature is applied [20,40], which is defined as…”

Section: Heat Transfer Coefficients and Nusselt Numbersmentioning

confidence: 99%

“…All of the measurements were made for fully developed flows with small oscillating velocity amplitudes. Heat transfer in pulsating turbulent flow was also experimentally studied and a variety of confusable results were reported: the frequency had no direct effect on the Nusselt number [11], no heat transfer enhancement was found [12,13], a slight heat transfer reduction was found [14], the change in Nusselt number was negative below a certain frequency and positive above it [15], heat transfer enhancement could occur only when the oscillating frequency was higher than a certain value [16,17], the heat transfer coefficient increased with the pressure oscillation amplitude [18], high frequencies and large oscillation amplitudes promoted heat transfer enhancement, especially at low Reynolds numbers [19], Nusselt number was found to increase with both pulsation amplitude and frequency in a square-sectional duct [20] and so on. Among those experiments, most studies were performed under the condition of small oscillating velocity amplitudes except the works reported in Refs.…”

Section: Introductionmentioning

confidence: 99%

“…Among those experiments, most studies were performed under the condition of small oscillating velocity amplitudes except the works reported in Refs. [20,21]. Recently, Gbadebo et al [22] experimentally studied heat transfer in the thermal entrance region of pulsating turbulent pipe flows under uniform heat flux conditions.…”

Section: Introductionmentioning

confidence: 99%

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Numerical analysis of heat transfer in pulsating turbulent flow in a pipe

Wang¹,

Zhang²

2005

International Journal of Heat and Mass Transfer

105

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Convection heat transfer in pulsating turbulent flow with large velocity oscillating amplitudes in a pipe at constant wall temperature is numerically studied. A low-Reynolds-number (LRN) k-e turbulent model is used in the turbulence modeling. The model analysis indicates that Womersley number is a very important parameter in the study of pulsating flow and heat transfer. Flow and heat transfer in a wide range of process parameters are investigated to reveal the velocity and temperature characteristics of the flow. The numerical calculation results show that in a pulsating turbulent flow there is an optimum Womersley number at which heat transfer is maximally enhanced. Both larger amplitude of velocity oscillation and flow reversal in the pulsating turbulent flow also greatly promote the heat transfer enhancement.

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Section: The Effect Of Temperature Oscillation At Inletsupporting

confidence: 84%

“…(16) loses its physical meaning. In this case, the section-average temperature is applied [20,40], which is defined as…”

Section: Heat Transfer Coefficients and Nusselt Numbersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Numerical analysis of heat transfer in pulsating turbulent flow in a pipe

Wang¹,

Zhang²

2005

International Journal of Heat and Mass Transfer

105

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“…However, some available results are contradictory and the main question is still open: Does pulsation enhance or else degrade heat transfer compared to steady flow. Pulsating flows have been investigated in many experimental configurations: Dec et al [1], [2] have studied the impact of the pulsation frequency, pulsation amplitude, and the mean flow rate on heat transfers in the tail pipe of a pulse combustor. Spatially averaged Nusselt number computations have shown that heat transfers increase with both pulsation amplitude and frequency.…”

Section: Introductionmentioning

confidence: 99%

Heat Transfer Investigation in Engine Exhaust-Type Pulsating Flow

Simonetti¹,

Caillol²,

Higelin³

et al. 2017

Proceedings of the 4th International Conference of Fluid Flow, Heat and Mass Transfer (FFHMT'17)

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-There are many engineering practical situations where heat is transferred under conditions of pulsating flow such as in the exhaust pipes of Internal Combustion Engines. In these conditions, heat transfer mechanism is affected by the pulsating flow parameters. The objective of the present work is to experimentally investigate heat transfers for pulsatile turbulent flows in a pipe. A unique experimental apparatus able to reproduce a pulsating flow representative of the engine exhaust has been designed. A stationary turbulent hot air flow with a Reynolds number of 30000, based on the time average 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 are evaluated. It has been observed that flow pulsation enhances convective heat transfers in comparison with the steady case. The test-bench architecture let us to evidence that, when the flow is excited with a pulsation frequency equal to one of the resonance modes of the system, a local maximum of the heat transfers rate appears. Such behaviour has been found to be independent of the pipe length. Results also show that the actual Nusselt correlations to predict convective heat transfer are inaccurate for pulsating flows, suggesting that new correlations which account pulsation effects have to be proposed.

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Experimental and modeling studies of a multi-tailpipe on a pulse combustor system

Yang

Yin³

2016

Int. J. Energy Res.

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Summary The effect of a multi‐tailpipe structure on a pulse combustor with an exhaust decoupler and a vent pipe is investigated. A nonlinear theoretical model is established, and corresponding experiments are made to verify the theoretical model. The results show that the multi‐tailpipe structure has two effects: It enhances the exhaust gas resistance and decreases exhaust gas velocity in the tailpipe; it also expands the tailpipe heat dissipation area and increases the heat loss. The amplitude of pressure fluctuations in the combustion chamber and exhaust decoupler is determined by competition between the strengthening effect of tailpipe resistance and the weakening effect of heat loss from the tailpipe. Frequency and pressure characteristics are dominated by tailpipe resistance and tailpipe heat loss. The working region is divided into three parts for different structure parameters: low frequency inphase zone, unstable zone, and high‐frequency antiphase zone. Tailpipe resistance only affects the unstable zone, and the necessary value of tailpipe friction exists to minimize the unstable zone. Heat loss from the tailpipe can reduce the unstable zone and cause it to squeeze the inphase zone, resulting in shrinkage of the inphase zone. Copyright © 2016 John Wiley & Sons, Ltd.

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Heat transfer enhancement in the oscillating turbulent flow of a pulse combustor tail pipe

Cited by 69 publications

References 15 publications

Numerical analysis of heat transfer in pulsating turbulent flow in a pipe

Numerical analysis of heat transfer in pulsating turbulent flow in a pipe

Heat Transfer Investigation in Engine Exhaust-Type Pulsating Flow

Experimental and modeling studies of a multi-tailpipe on a pulse combustor system

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