Heat transfer in curved tubes with pulsating flow

Rabadi, N. J.; Chow, J. C. F.; Simon, H.

doi:10.1016/0017-9310(82)90005-9

Cited by 17 publications

(8 citation statements)

References 3 publications

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“…8, the effect of pulsating flow on the heat transfer coefficient is more significant at high values of Reynolds number (flow rate), due to higher turbulence intensity [9,48,51,52]. Finally, the Secondary flow can be originated from the axial flow and therefore, it can be stated that intensification of the secondary flow and increasing temperature and velocity gradients near the outer wall at some moments of the cycle, radial and longitudinal mixing enhancement and the occurrence of secondary flow reversal play more important roles on the heat transfer improvement [17][18][19].…”

Section: Heat Transfer In Pulsating Flow Of Base Fluidmentioning

confidence: 95%

“…They reported that augmentation of time averaged Nusselt number is obvious at high Prandtl numbers, high excitation relative amplitudes, and low excitation frequencies. Based on the other research, Rabadi et al [17] studied effects of pulsatile flow upon heat transfer characteristics in curved tubes under axially uniform heat flux boundary conditions with peripherally uniform wall temperature. The conflicting results were reported compared with the above-stated perturbation analysis.…”

Section: Introductionmentioning

confidence: 99%

“…As an active technique, pulsation in fluid flow is another method of heat transfer enhancement. Widespread studies have been allocated to pulsating flows and their associated heat transfer problems over the past decades [8][9][10][11][12][13][14][15][16][17][18][19][20][21]. Martinelli et al [8] initiated the work on heat transfer characteristics of pulsating flow in 1943.…”

Section: Introductionmentioning

confidence: 99%

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Characteristics of heat transfer and flow of Al2O3/water nanofluid in a spiral-coil tube for turbulent pulsating flow

et al. 2015

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K Thermal conductivity (W/m K) L Length of tube (m) m Mass flow rate (kg/s) N Revolution per minute of the rotating valve spindle (rpm) Pe Peclet number Pr Prandtl number Q Heat transfer rate (W) r Inner radius of tube (m) R Radius of spiral coil (m) Re Reynolds number T Temperature (K) U Average overall heat transfer coefficient (W/m 2 K) V Average velocity of mean flow (m/s) Wo Womersly number, Wo = D i 2 υ ω Greek letters α Thermal diffusivity (m 2 /s) µ Dynamic viscosity (kg/m s) ρ Density (kg/m 3 ) υ Kinematic viscosity (m 2 /s) ω Angular pulsation frequency (1/s) ∞ Ambient medium ϕ Nanoparticle volumetric fraction Superscript -Average Subscripts ave Average i Inlet m Mean o Outlet pu Pulsated st SteadyAbstract In the past two decades, enhancement of heat transfer characteristics of original fluid using nanofluids has been proposed by a large number of researchers. In this paper, an experimental study was carried out to investigate effect of pulsation on heat transfer of fluid flow inside a spiral-coil tube. In order to perform the experiments, a hot water reservoir tank was prepared and the spiral-coil was immersed horizontally inside the tank. Average temperature of the hot water bath was kept constant at 60 °C to establish a quiescent region of uniform temperature. The experiments were conducted in turbulent flow regime using distilled water and Al 2 O 3 /water nanofluid at 0.5, 1, and 1.5 % particle volume concentration. Results showed that overall heat transfer coefficient of the base fluid flow increases by using nanofluid or pulsation into the base fluid flow up to 14 %. Heat transfer results also indicated that combination of the nanofluid and the pulsation into the fluid flow can increase significantly the overall heat transfer coefficient up to 23 %. List of symbolsA Inside heat transfer area (m 2 ) C p Specific heat capacity (J/kg K) D i Inner diameter of tube (m) f Frequency (Hz)

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Section: Heat Transfer In Pulsating Flow Of Base Fluidmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Characteristics of heat transfer and flow of Al2O3/water nanofluid in a spiral-coil tube for turbulent pulsating flow

et al. 2015

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“…There is no previous work looking into the synergistic effects of longitudinal ribs and reciprocation on heat transfer in a curved duct. Only a few of relevant studies examine the flow and heat transfer in static curved channels which are subject to externally imposed streamwise pulsating or oscillatory pres- sure waves [17][18][19][20]. Studies of pulsating and oscillatory flows in a static curved channel offer the background knowledge for understanding the dynamic nature of secondary flows in a curved channel [17][18][19][20].…”

Section: Industrial Backgroundmentioning

confidence: 99%

Heat transfer in a reciprocating curved square duct fitted with longitudinal ribs

Chang¹,

Lin²,

Liou³

2008

International Journal of Thermal Sciences

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“…The same observation was made by Habib et al [20] in their experimental investigation. Rabadi et al [26] also considered laminar pulsating flow in curved tubes and found that the timeaveraged heat transfer coefficient is comparatively large for large Prandtl numbers Pr and falls at low frequencies, which is clearly shown as the oscillation amplitude increases. In [27], the influence of the Grashof number Gr and Re on heat transfer characteristics in a parallel vertical open channel was demonstrated.…”

Section: Introductionmentioning

confidence: 94%

Effects of Flow Pulsation on Forced Convection in a Channel Containing Regularly Spaced Nonconducting Fins

2010

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The effects of pulsating flow on forced convection in a rectangular channel containing a series of regularly spaced, nonconducting inserts were investigated experimentally. Based on the experimental data, a correlation equation was developed. The steady-flow Reynolds number Re in the laminar range, Re < 1200, was examined. The Prandtl number of the working fluid Pr = 15 and the oscillation was generated using low-frequency oscillation at f < 50 Hz and amplitude A < 1 mm. The energy dissipation as a result of applied oscillation was determined by phase-resolved measurements of pressure difference and liquid displacement. The system shows improved convective heat transfer towards a low Reynolds number. At a higher Reynolds number, the influence of the oscillation diminished and the flow approaches a steady finned flow. The predictions of the developed correlation equation are in good agreement with the experimental data. The calculated power input due to oscillation is comparatively low and decreases towards increasing net flow rates where the oscillating flow has a diminishing effect.

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Heat transfer in curved tubes with pulsating flow

Cited by 17 publications

References 3 publications

Characteristics of heat transfer and flow of Al2O3/water nanofluid in a spiral-coil tube for turbulent pulsating flow

Characteristics of heat transfer and flow of Al2O3/water nanofluid in a spiral-coil tube for turbulent pulsating flow

Heat transfer in a reciprocating curved square duct fitted with longitudinal ribs

Effects of Flow Pulsation on Forced Convection in a Channel Containing Regularly Spaced Nonconducting Fins

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