Experimental study on functionality of surfactant solution in turbulent heat transfer by varying local shear rate

Tsukahara, Takahiro; Hara, Shumpei; Kawada, Shinya; Kawaguchi, Yasuo

doi:10.1016/j.ijheatmasstransfer.2016.06.024

Cited by 5 publications

(3 citation statements)

References 39 publications

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“…Through the creation of larger structures such as micelles and micellar networks, turbulent mixing behaviours, as well as non-Newtonian viscosity behaviours not only influence the pipe pressure drops but also the heat transfer within the fluid. [14][15][16] On a molecular scale, surfactant surface affinity has been shown to influence near wall heat transfer. 17 Although it is not the purpose of this paper to review every way in which heat transfer behaviour can be modified within a fluid, it is clear from the sample of literature referred to that modification of fluid heat transfer is not only possible but commonplace in a variety of existing applications.…”

Section: Introductionmentioning

confidence: 99%

Opportunities for improved space heating energy efficiency from fluid property modifications

Williams

Innerdale

2022

Indoor and Built Environment

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Unsteady behaviour of hydronic heating systems causes higher mean room temperatures than are required for comfort. Peak room temperatures depend on interactions between thermostats, heat emitters and the room. The importance of fluid properties on such unsteady heating is often misunderstood meaning potential energy savings are overlooked. This paper demonstrates the influence of fluid modifications and indicates a plausible magnitude of the energy saving opportunity. The results showed that fluid side heat transfer coefficient in isolation had negligible effect. Specific heat capacity of the fluid and flow rates were important, as they altered the amount of embedded energy in the heat emitter when thermostat conditions were met. Reductions in mean heating power for steady demand conditions were between 0 and 7% for plausible changes to fluid properties, depending on heat emitter size, room insulation and external temperature. Reductions in individual cycle energy were between 5 and 25%. When considered in the context of intermittent finite duration heating events, those that contained a small number of thermostat cycles demonstrated energy savings that tended towards the reductions in individual cycle energy. Heating events with larger numbers of cycles showed energy savings tending towards the reduction in mean heating power.

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Section: Introductionmentioning

confidence: 99%

Opportunities for improved space heating energy efficiency from fluid property modifications

Williams

Innerdale

2022

Indoor and Built Environment

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“…There is a critical Reynolds number for each drag-reducing solution with a fixed concentration. If the Reynolds number is larger than the critical value, the drag reduction function will lose due to the collapse of shear induced structures of micelles (Tsukahara et al, 2016;Wei et al, 2012;Xu et al, 2016). Different from molecular structures of polymers, the shear induced structures are regenerative for the dragreducing solution of surfactants when the external conditions (such as the strong shear or the high temperature) are removed (Kim et al, 2011;Matras et al, 2008;Pang et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation on Drag Reduction of Mixed Peo and Ctac/Nasal Aqueous Solution in a Rotating Disk Apparatus

Tian¹,

Pang²,

Xu³

2021

Frontiers in Heat and Mass Transfer

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Drag reduction (DR) by the additive of mixed surfactant and polymer is investigated in detail in a rotating disk apparatus (RDA). Polyethylene oxide (PEO) and Cetyltrimethyl ammonium chloride (CTAC)/sodium salicylate (NaSal) are chosen as polymer and surfactant, respectively. It is investigated on the influence of combination concentration of polymer & surfactant, temperature and Reynolds number on the drag-reducing rate. The present experimental results show that the drag-reducing rate of the mixed solution is definitely higher than that of the pure PEO or CTAC/NaSal solutions. This phenomenon is especially sharp at the high temperature and/or the large Reynolds number. When the temperature is higher than 30℃, the net enhancement of DR is the sharpest for the mixed solutions of any CTAC/NaSal concentration and 30 ppm PEO. However, for the mixed solutions of the fixed PEO concentration, the combination concentration of PEO & CTAC/NaSal, which causes the sharpest enhancement of the DR, depends on temperature. In short, comparing with the only addition of PEO or CTAC/NaSal, the coupled addition of PEO & CTAC/NaSal can obtain the very good drag-reducing effect for the rotating disk apparatus at the high temperature and/or the great Reynolds number.

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“…Wei et al 15 used the particle image velocimetry (PIV) technique to investigate the turbulent structures of surfactant solution and found that the formation of small-scale vortices was inhibited by adding the surfactants, implying a large-eddy environment which could provide an excellent condition for other drag-reducing methods related to the vortex scale. Furthermore, Ma et al 16 and Tsukahara et al 17 both reported that the drag reduction and heat transfer performance of surfactant restrain each other, which limited its application in the field of heat transfer. Wang et al 18 reported that the drag reduction performance of surfactant solution was lower at a low Reynolds number (Re < 10,000), due to the lower shear stress and the weaker shear-induced structures, which limited the application of surfactant solutions in the field of low-speed.…”

Section: Introductionmentioning

confidence: 99%

Direct numerical simulation of surfactant solution flow in the wide‐rib rectangular grooved channel

et al. 2018

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The turbulent flow of surfactant solution in the wide‐rib rectangular grooved channels was studied by direct numerical simulation. Moreover, the variations of near‐wall streamwise vortices with time were discussed and the distributions of streamwise vortex radius, swirling strength and density were quantitatively investigated. It was found that the influence of microgrooves on the fluid mainly occurred within the buffer layer and microgrooves could induce numerous streamwise vortices with small size and swirling strength within the grooved valleys. The drag‐reducing enhancement mechanism of microgroove in the surfactant solution could be mainly considered as the competing results between the “restriction effect” and “tip effect” of microgroove, and the essential factor should be the numerous secondary streamwise vortices with small size and swirling strength within the grooved valleys. Furthermore, a predicted method for the optimal drag‐reducing size of microgroove was proposed, and the prediction values agreed well with the numerical results. © 2018 American Institute of Chemical Engineers AIChE J, 64: 2898–2912, 2018

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Experimental study on functionality of surfactant solution in turbulent heat transfer by varying local shear rate

Cited by 5 publications

References 39 publications

Opportunities for improved space heating energy efficiency from fluid property modifications

Opportunities for improved space heating energy efficiency from fluid property modifications

Experimental Investigation on Drag Reduction of Mixed Peo and Ctac/Nasal Aqueous Solution in a Rotating Disk Apparatus

Direct numerical simulation of surfactant solution flow in the wide‐rib rectangular grooved channel

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