The Natural Convection Heat Transfer Performance Of CTAB Micelle Solution

In recent years,the application of micellar solutions drag-reducing fluids in regional heating or cooling systems has become a hot topic of concern.However,the natural convection heat transfer mechanism of micellar solutions is not clear.In this paper,in order to study the natural convection heat transfer performance of micellar solutions,the natural convection heat-transfer performance of cetyltrimethyl ammonium bromide(CTAB)micelle solution has been studied.The main contents of the study are listed as follows:1)The natural convection heat transfer experiment system was designed and commissioned.The natural convection heat-transfer of water near uniform temperature vertical plate was studied.The experimental results showed that the experimental correlations of the laminar and the turbulence were within 4.5%and 4.4%error in contrast to McAdams and Fujii results respectively,which were in the range of the engineering experiment allowable error.The experimental system and method are reliable,and the precision is high.2)In the test,the apparent viscosities with shear rate of CTAB with sodium salicylate(NaSal)and trans-chlorocinnamic acid(trans-pClCA)were studied.The relationships between the zero shear viscosity acquired by Cross model,the characteristic time and the temperature were in accordance with the Arrhenius equation,which the correlations were above 0.9 and could be used for CTAB micelle solution natural convective heat transfer experiment and numerical simulation researches.3)The effects of CTAB solution concentration and heating wall surface temperature on the flow state in the boundary layer near the uniform temperature vertical plate were investigated.The results showed that the higher the concentration,the lower the heating wall surface temperature,the wider the laminar flow in the boundary layer.4)The effects of micelle solutions viscoelasticity on natural heat transfer were studied.The results showed that the higher the viscoelasticity parameter We,the lower the input power of the uniform vertical plate and the lower the Nux.The non-dimensional equations between Nux and Rax and We2/Pr were established for the two kinds of micelle solutions,which could be used to calculate micelle solutions natural convection heat transfer Nux in the range of Rax=105.5-1011.5 and We2/Pr=0.00015-0.0005.5)Based on the shear-thinning Cross model,the natural convection of the CTAB/trans-pClCA micellar solution near the uniform vertical plate in the cavity was simulated.The results showed that,in the range of Ra = 105.5-108,the calculation Nu and experimental Nu were within ± 5%error,and numerical simulation combined with Cross equation could be used to predict natural convective heat transfer NuL of micellar solutions.The effects of heating wall surface temperatures,micelle solution concentrations and Ra on the natural convection flow and heat transfer of CTAB/trans-pCICA micellar solution were analyzed through numerical simulation.The results showed that the higher the temperature of the heating wall surface,the lower the concentration of the micellar soluion and the bigger the Ra,the velocity vector layer was thinner,the isothermal line near wall was steeper,the isothermal lines in the micelle solution main body were more vertical to the heating wall,the thinner the laminar boundary layer near the wall,and the better the natural convective heat transfer.