Simulation of heat transfer to separation Air flow in a concentric pipe

Oon, Cheen Sean; Al-Shamma’a, Ahmed; Kazi, S. N.; Chew, Bee Teng; Badarudin, A.; Sadeghinezhad, Emad

doi:10.1016/j.icheatmasstransfer.2014.07.008

Cited by 10 publications

(4 citation statements)

References 20 publications

(16 reference statements)

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“…The third, both the probe cantilevers and the upper surfaces of THF hydrate sample have heat exchange with the ambient air. In the case of numerical simulation, it is considered that the convective heat q between the probe and the air per unit area is the convective heat exchange coefficient h multiplied by their temperature difference T probe − T air [17, 18] which can be expressed as follows: q=hTprobe−Tair.…”

Section: Thermal Conduction Modelmentioning

confidence: 99%

Influence of AFM Tip Temperature on THF Hydrate Stability: Theoretical Model and Numerical Simulation

Peng

Ning

et al. 2019

Scanning

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Atomic force microscopy (AFM) indentation is widely used to determine mechanical parameters of various materials. However, AFM tip may lead to phase transition of the cold sample in the region of contact area. It is a long-standing challenge that low-temperature phase-change materials (e.g., ice and hydrate) are hardly characterized by AFM, especially for clathrate hydrates. Here, with theoretical analysis and numerical simulation, we investigated the temperature influence of AFM tip on the tetrahydrofuran (THF) hydrate stability. At first, a steady-state model of heat conduction was established between a v-shaped probe and THF hydrate sample. The temperature of the tip was estimated at different laser spot positions and laser intensities. Through numerical simulation, the heat loss by air convection is less than 1% of the total laser heat, and the influence of ambient air on the AFM probe temperature can be neglected. Meanwhile, the local temperature in the region of contact area was also calculated at the THF hydrate temperature of 0°C, -10°C, -20°C, and -30°C. We found out that the AFM tip causes the cold THF hydrate to melt. The thermal melting thickness decreases with the reduction of laser intensity and THF hydrate temperature. On the contrary, it is positively correlated with the thickness of liquid-like layer on THF hydrate surface and is also linearly increased with the contact radius. This indicates that the thermal melting continues as the press-in depth of the tip into THF hydrate increases. The local temperature rises when the tip touches the THF hydrate. It is easier for THF hydrate to be melted by an external pressure. In addition, the proposed model may be useful for guiding force tests on low-temperature phase-change materials by the AFM indentation.

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Section: Thermal Conduction Modelmentioning

confidence: 99%

Influence of AFM Tip Temperature on THF Hydrate Stability: Theoretical Model and Numerical Simulation

Peng

Ning

et al. 2019

Scanning

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“…Thermal and physical properties of nanofluids such as thermal conductivity, specific heat, density and viscocity of nanofluids can be obtained by several suggested correlations (Pak and Cho 1998;Yu and Choi 2003;Drew and Passman 2006;Oon et al, 2014). The thermal conductivity of water-based TiO 2 nanofluids can be calculated by using Eq.…”

Section: Data Processingmentioning

confidence: 99%

INCREASE IN CONVECTIVE HEAT TRANSFER OVER A BACKWARD-FACING STEP IMMERSED IN A WATER-BASED TiO2 NANOFLUID

et al. 2018

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Investigation of flow separation and reattachment of 0.2% water-based TiO 2 nanofluid in an annular sudden expansion is presented in this paper. Such flows occur in various engineering and heat transfer applications. Computational fluid dynamics package (FLUENT) is used to study turbulent nanofluid flow in this research. Only a quarter of the annular pipe is developed and simulated as it has symmetrical geometry. Standard k-epsilon second order implicit, pressure based-solver equations are applied. Reynolds numbers between 17050 and 44545, step height ratio of 1.82 and constant heat flux of 49050 W/m 2 were utilized in the simulation. Numerical simulation results show that with the increase of Reynolds number increases the heat transfer coefficient and the Nusselt number. Moreover, the surface temperature dropped to its lowest value after the expansion and then gradually increased along the pipe.

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“…The FLUENT commercial code based on finite volume method, which has been used in some previous works [ 29 – 31 ], was applied to solve the Reynolds Averaged Navier-Stokes (RANS) equations. This method is based on a particular type of the residual weighting approach.…”

Section: Numerical Proceduresmentioning

confidence: 99%

Indoor Solar Thermal Energy Saving Time with Phase Change Material in a Horizontal Shell and Finned‐Tube Heat Exchanger

Paria

Sarhan

Goodarzi

et al. 2015

The Scientific World Journal

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An experimental as well as numerical investigation was conducted on the melting/solidification processes of a stationary phase change material (PCM) in a shell around a finned-tube heat exchanger system. The PCM was stored in the horizontal annular space between a shell and finned-tube where distilled water was employed as the heat transfer fluid (HTF). The focus of this study was on the behavior of PCM for storage (charging or melting) and removal (discharging or solidification), as well as the effect of flow rate on the charged and discharged solar thermal energy. The impact of the Reynolds number was determined and the results were compared with each other to reveal the changes in amount of stored thermal energy with the variation of heat transfer fluid flow rates. The results showed that, by increasing the Reynolds number from 1000 to 2000, the total melting time decreases by 58%. The process of solidification also will speed up with increasing Reynolds number in the discharging process. The results also indicated that the fluctuation of gradient temperature decreased and became smooth with increasing Reynolds number. As a result, by increasing the Reynolds number in the charging process, the theoretical efficiency rises.

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Simulation of heat transfer to separation Air flow in a concentric pipe

Cited by 10 publications

References 20 publications

Influence of AFM Tip Temperature on THF Hydrate Stability: Theoretical Model and Numerical Simulation

Influence of AFM Tip Temperature on THF Hydrate Stability: Theoretical Model and Numerical Simulation

INCREASE IN CONVECTIVE HEAT TRANSFER OVER A BACKWARD-FACING STEP IMMERSED IN A WATER-BASED TiO2 NANOFLUID

Indoor Solar Thermal Energy Saving Time with Phase Change Material in a Horizontal Shell and Finned‐Tube Heat Exchanger

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