The thermal and transport characteristics of nanofluids in a novel three‐dimensional device

Abstract

The augmentation in heat transfer can be achieved by improving either transport phenomena with geometry perturbation or thermal conductivity of the fluid itself. In the present study, the simultaneous effects of both the geometry and improved thermal conductivity have been tried on heat transfer enhancement by using two different nanofluids (Al 2 O 3 -water and TiO 2 -water). An innovative three-dimensional device called a coiled flow inverter (CFI) is proposed for the process intensification. The CFI is made up of helical coiled tube, which is bent periodically to 90 8 at equidistant length. In addition to a CFI, the performance characteristics of helical coil and straight tube have been investigated. The Reynolds numbers are in the range of 25-4000, while the nanoparticle volume fraction varied from 0.25-4 %. It was noted that the heat transfer in a CFI improved considerably as compared to helical coil and straight tube of same dimension. The Nusselt number in helical coil augments by 2.5 times to that of straight tube. In the CFI, the Nusselt number further enhanced by 23-35 % as compared to helical coil, with 0-4 % increase in the nanoparticle volume fractions. The new correlations are developed to predict the Nusselt number and friction factor for the flow of nanofluids in the CFI. The number of merit in the CFI to that of straight tube are 1.6-1.8 times, with 0-4 % nanoparticle volume fractions. The present study may motivate the design and development of novel compact heat exchangers as well as a new-generation microfluidic device.

Numerical Study of Heat Transfer Enhancement for Laminar Nanofluids Flow

“…Figure 1ashows a good agreement of the present results with the literature[21,48] for water-based Al 2 O 3 nanofluid at φ b = 1%. The Nu results were also validated for constant wall temperature condition as shown in Figure 1b.…”

“…of Maïga et al [21] and the computational results of Singh et al [48] for constant heat flux condition. Figure 1a shows a good agreement of the present results with the literature [21,48] for water-based Al2O3 nanofluid at = 1%. The Nu results were also validated for constant wall temperature condition as shown in Figure 1b.…”

“…An extensive number of numerical simulations were performed to determine the HTC enhancement of laminar nanofluids. For validation purpose, the present results of the Nu for straight tube were compared with the correlation (Nu = 0.086Re 0.55 Pr 0.5 ) of Maïga et al [21] and the computational results of Singh et al [48] for constant heat flux condition. The Nusselt number (Nu), was defined as:…”

Utilization of milli-scale coiled flow inverter in combination with phase separator for continuous flow liquid–liquid extraction processes

“…CFI was shown to be very effective as a heat exchanger [61,[91][92][93][94] and as an inline mixer of two miscible liquids [58,59] Furthermore, it was used for chemical reaction [95] and to study fluid flow in two-phase gas-liquid systems [60,[96][97][98]. It was found to have residence time distribution close to an ideal plug flow reactor [99,100].…”

How do you write and present research well? Q4 – Do not metastasize with metadiscourse

“…One may use either different existing formulae derived for two-phase mixtures, such as the Brinkman relationship, [37] or, in some cases, correlations derived from available experimental data. [23] [p. 2189]…”