In this article, distilled water and CuO particles with volume fraction of 1%, 2% and 4% are numerically studied. The steady state flow regime is considered laminar with Reynolds number of 100, and nano-particles diameters are assumed 20 nm and 80 nm. The hydraulic diameter and the length of equilateral triangular channel are 8 mm and 1000 mm, respectively. The problem is solved for two different boundary conditions; firstly, constant heat flux for all sides as a validation approach; and secondly, constant heat flux for two sides and constant temperature for one side (hot plate). Convective heat transfer coefficient, Nusselt number, pressure loss through the channel, velocity distribution in cross section and temperature distribution on walls are investigated in detail. The fluid flow is supposed to be one-phase flow. It can be observed that nano-fluid leads to a remarkable enhancement on heat transfer coefficient. Furthermore, CuO particles increase pressure loss through the channel and velocity distribution in fully developed cross section of channel, as well. The computations reveal that the size of nano-particles has no significant influence on heat transfer properties. Besides, the study shows a good agreement between provided outcomes and experimental data available in the literature.

Numerical simulation of laminar forced convection of water-CuO nanofluid inside a triangular duct

Significance of nanoparticles' shape and thermo-hydrodynamic slip constraints on MHD alumina-water nanoliquid flows over a rotating heated disk: The passive control approach

In this study, thermal performance and flow characteristics of a shell and tube heat exchanger equipped with various baffle angles were studied. The heat exchanger was operated with distilled water, and a hybrid nanofluid at three concentrations of 0.04% and 0.10% of GNP-Ag/water within Reynolds numbers ranged between 10,000 and 20,000. The thermophysical properties of nanofluid varied with temperature and nanoparticles’ concentration. The baffle angles were set at 45°, 90°, 135°, and 180°. Results showed that the calculated Nusselt number (Nu) could be improved by adding nanoparticles to the distilled water or increasing the fluid’s Reynolds number. At a low Re number, the Nu corresponding to baffle angle of 135° was very close to that recorded for the angle of 180°. At Re = 20,000, the Nu number was the highest (by 35% compared to the reference case), belonging to a baffle angle of 135°. Additionally, results related to friction factor and pressure drop showed that more locations with fluid blocking were observed by increasing the baffle angle, resulting in increased pressure drop value and friction. Finally, the temperature streamlines counter showed that the best baffle angle could be 135° in which maximum heat removal and the best thermal performance can be observed.

https://www.mdpi.com/2227-7390/9/8/881/pdf

Combination Effect of Baffle Arrangement and Hybrid Nanofluid on Thermal Performance of a Shell and Tube Heat Exchanger Using 3-D Homogeneous Mixture Model

In order to discuss the surface pressure pulsation characteristics of the magnetic-fluid sealing membrane of centrifugal pump, this paper studies the surface pressure pulsation characteristics of the shaft end sealing membrane under different flow operating conditions of centrifugal pump based on the combination of numerical calculation and experimental verification. The results show that the pressure value on the surface of the magnetic-fluid sealing film decreases with the increase of the flow rate of the centrifugal pump, and the pressure on the surface of the magnetic-fluid sealing film has periodic pulsation, and the period is the time required for a single blade to sweep the volute separating tongue. In one rotation cycle of the runner, the number of reciprocating movements of the magnetic-hydraulic sealing film is the same as the number of blades of the runner. The main reason for the pressure pulsation is that the impeller periodically sweeps the fixed surface of the centrifugal pump.

/pdf/analysis-of-surface-pressure-pulsation-characteristics-of-2w7zxsll.pdf

Analysis of Surface Pressure Pulsation Characteristics of Centrifugal Pump Magnetic Liquid Sealing Film

A combined numerical and experimental study on the forced convection of Al2O3-water nanofluid in a circular tube

Experimental study on cooling performance of nanofluid flow in a horizontal circular tube

The role of water content in rate dependence of tensile strength of a fine-grained sandstone

Laminar forced convection effectiveness of Al2O3–water nanofluid flow in a circular tube at various operation temperatures: Effects of temperature-dependent properties

In this work, the cooling effectiveness and entropy production of aluminum oxide–water nanofluid flow and heat transfer in the circular tube with the wall conduction effects are explored. All values of heat transfer effectiveness ratios are more than unity in this study. For a constant value of nanoparticles concentration, both heat transfer effectiveness ratios increase as the input temperature of fluid is increased. Both heat transfer effectiveness ratios are increased as the concentration of nanoparticles increases. Predictions show that all values of dimensionless local entropy production ratio are less than unity in this study except in the areas near the entrance of the heating part. This means that the usage of nanofluid is beneficial for decreasing the irreversibility of the system. The dimensionless local entropy production ratio decreases when the input temperature of fluid increases. The maximum value of Biw = 5 × 10-4 was reported for the Biot number in this study, which is far less than 0.1. As a consequence, the tube wall can be regarded as a Lumped system, and it is a reasonable assumption to ignore the radial thermal resistance.

Cooling characteristics and entropy production of nanofluid flowing through tube

The influence of sediment media on the blade pressure and cavitation of a tubular turbine was investigated in this study. The Zwart–Geber–Belamri cavitation model and the shear stress transport k–w turbulence model were applied to numerically simulate and experimentally validate the full flow path of the tubular turbine under combined conditions for sediment particle sizes of 0.01 and 0.05 mm and concentrations of 1%, 1.5%, and 2%. The results show that the pressure of the blade increases with the sediment concentration. Cavitation mainly occurs between the blade shroud and the leading edge. The higher the sediment concentration, the lower the vapor volume fraction at the same sediment particle size. The presence of sediments inhibits further cavitation development, and the inhibition effect is significant. At the same concentration, the larger the particle size of the sediment, the lower the vapor volume fraction. Thus, the increase in the particle size inhibits cavitation, but the inhibition effect is not significant.

/pdf/influence-of-solid-liquid-two-phase-flow-on-cavitation-of-v9e5q9ps.pdf

Chu Yun Cheng

Papers

Experimental study on cooling performance of nanofluid flow in a horizontal circular tube

The role of water content in rate dependence of tensile strength of a fine-grained sandstone

Laminar forced convection effectiveness of Al2O3–water nanofluid flow in a circular tube at various operation temperatures: Effects of temperature-dependent properties

Cooling characteristics and entropy production of nanofluid flowing through tube

Influence of Solid–Liquid Two-Phase Flow on Cavitation of Tubular Turbine Blades Under Combined Conditions