Metal foam has recently been used in many engineering applications, such as solar collectors, heat exchangers, and cooling of electronic devices, which calls for studying different cases of using metal foam in these applications. The current study conducts a numerical analysis of heat transfer and fluid flow characteristics for air in a rectangular channel filled with high-porosity copper foam. The study examined the thermal performance for two cases of gradient pore density, which are arranged as (10-20-40) PPI and (40-20-10) PPI. These cases were compared with two other cases for constant pore density, 10 and 40 PPI, and empty cases. The ANSYS FLUENT 20.0 employed the Darcy-Forchheimer extended Brickman model in the two-dimensional domain with the local thermal non-equilibrium model (LTNE) for the energy equation to obtain the numerical simulation for this study. The working parameters included air with Re from 200 to 2100 and applied heat flux from 450 to 6000 W/m2. The results indicated that employing metal foam with a low pore density led to a decrease in both the Nusselt number and pressure drop. Both gradient cases exhibited Nusselt numbers and friction factors that fell within the range of the constant PPI cases, but one of the gradient cases increased the performance factor by 10%. In general, the PPI configuration of 10-20-40 exhibited a higher heat transfer coefficient in comparison to the 40-20-10 PPI arrangement with the same pressure drop.
Although renewable energy systems have become an interesting global issue, it is not continuous either daily or seasonally. Latent heat energy storage (LHES) is one of the suitable solutions for this problem. LHES becomes a basic element in renewable energy systems. LHES compensate for the energy lack when these systems are at low production conditions. The present work considered a shell and tube LHES for numerical investigation of the tube rotation influence on the melting process. The simulation and calculations were carried out using ANSYS Fluent software. Paraffin wax represents the phase change material (PCM) in this work, while water was selected to be the heat transfer fluid (HTF). The calculations were carried o
... Show MoreMany researchers used different methods in their investigations to enhance the heat transfer coefficient, one of these methods is using porous medium. Heat transfer process inside closed and open cavities filled with a fluid-saturated porous media has a considerable importance in different engineering applications, such as compact heat exchangers, nuclear reactors and solar collectors. So, the present paper comprises a review on natural, forced, and combined convection heat transfer inside a porous cavity with and without driven lid. Most of the researchers on this specific subject studied the effect of many parameters on the heat transfer and fluid field inside a porous cavity, like the angle of inclination, the presenc
... Show MoreThe aim of this work is to explore the thermal performance of a tracked tubular solar still (TSS) with a parabolic trough concentrator in Baghdad (33.27° N, 44.37° E) in September 2022. The present tubular still is distinguished by its hexagonal glass cover. The effect of integrating the TSS with a heat pipe, the still tilt angle (10°, 15°), and the depth of saline water inside the still partitions on the productivity of freshwater are investigated. The results showed that using heat pipe enhances the freshwater productivity by 25%–40% and the efficiency by 25%. For the still integrated with heat pipe, as the water depth is increased from 5.5 to 6.5 cm the productivity of freshwater is incre
An experimental study is made here to investigate the discharge coefficient for contracted rectangular Sharp crested weirs. Three Models are used, each with different weir width to flume width ratios (0.333, 0.5, and 0.666). The experimental work is conducted in a standard flume with high-precision head and flow measuring devices. Results are used to find a dimensionless equation for the discharge coefficient variation with geometrical, flow, and fluid properties. These are the ratio of the total head to the weir height, the ratio of the contracted weir width to the flume width, the ratio of the total head to the contracted width, and Reynolds and Weber numbers. Results show that the relationship between the discharge co
... Show MoreThe transfer of chemical pollutants from bottled water into water due to heat, sunlight and poor storage is one of the most serious threats to human health around the world, the objective of this study was to estimate the pH value and the transport of heavy metals from plastic bottles to water, for this purpose, 30 bottles of water for 10 local brands were collected and divided into three groups, the first was left at room temperature 25°C, The second was placed in a heat oven at 25°C and the third in another oven at 50°C for two weeks. The results showed significant differences at (P<0.05) between water samples, pH value and concentrations of heavy metals (Sb, Pb, Ni, Cu, Cr, Cd and Fe) we
... Show MoreThe research aims to reveal the methods of visual intertextuality used in the websites of the oriented satellite channel which is Arabic-speaking when addressing normalization with Israel. It also indicates the sources and types of intertextual images, the methodological and semiotic mechanisms for analyzing the intertextuality of news images used on the website of Alhurra satellite channel for the period from 1/6 - 30/8/2022, which included (94) images. The researcher analyzed (37) images with intertextual dimensions, excluding (57) images, which did not carry connotations connected with the inputs and objectives of the research.
The research reach
... Show MoreUltrasonic Extraction method followed by gradient HPLC was carried out for the simultaneous determination of four insecticides are [imidacloprid (Imi), thiamethoxam (Thi), indoxacarb (Ind) and abamectin (Aba)] used to combat the major insect pests in Iraq, whitefly, Dubas Bug, worms fruits as well as to combat the spiders – dream respectively in eco-soil samples. The extraction recovery was in the range of 99.77 to 109.1 %. The dissipation kinetics and residual levels of these insecticides in soil sample was studied under field ecosystem. The half-life of the mix insecticides was determined. The half-life was in range of 0.38 to 4.06 days with the soil samples were brought from the Agricultural Land called Nahrawan located in th
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