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Performance a double slope of the solar still Integrated With or without parabolic trough collector is investigated experimentally. To improve the output of a double slope solar still, a number of initiatives have been undertaken, using wax as a phase change material (PCM) with a parabolic trough collector. A parabolic trough collector (PTC) transfers incident solar energy to the solar still through a water tube connected to a heat exchanger embedded in used microcrystalline wax. Experiments were carried out after orienting the basin to the south and holding the water depth in the basin at 20 mm. According to the results obtained, the solar stills with parabolic trough collector have higher temperatures and productivity than solar stills without parabolic trough collector, as well as the ability to store latent heat energy in solar still, allowing fresh water to condense even after sunset. In addition, the parabolic trough collector with phase change material in the double slope solar improves productivity by 37.3 % and 42 %, respectively.

The present 3D numerical study was performed to show the effects of the length of central cut twisting tape (CCTT) on the characteristics of thermodynamic and hydrodynamic fields when this tape is inserted inside a tube in which, air is flows in turbulent pattern. Central cut twisting tapes of the same cut ratio (c = C/D) of 0.4 and four different length ratio (LR = l/L) of 0.25, 0.5, 0.75 and 1 were inserted in the tested tube that subjected to a uniform heat flux. The range of Reynolds number of air flow was 10000 ? Re ? 40000. Fluent in ANSYS 15 was used for problem designing, formulation and results obtaining in the present study. Finite volume method was the discretization method and tetrahedral type of mesh element was used. RNG k-? was chosen as the turbulent model. The obtained results showed that the increasing in Reynolds number leads to an increasing in Nusselt number and a decreasing in both friction factor and thermal performance factor. Also, these results cleared that the increasing in the length ratio of the studied type of twisting tape gives higher Nessult number, friction factors and thermal performance factor of 171.172, 0.0932 and 1.432 respectively

A numerical study is carried out on the perforation pipes with phase angles of 180° and 90° in a horizontal wellbore. To understand the effect of the above two-phase angles on the flow inside the wellbore, the CFD simulation of computational fluid dynamics is used. ANSYS FLUENT's simulation of the flow in the well has been used to calculate the pressure drop, friction factor, wall shear stress, productivity index, etc. The standard (k − 𝜀) model has been used to predict the turbulent behavior of radial flow. The conclusion showed that the overall pressure drop increase as the flow rate ratio increase which leads to an increase in the radial flow through the perforations, thereby keeping the axial flow through the pipe constant. Therefore, the percentage error of the total pressure drops for the phasing of the 180° and 90° perforations in test 5 is about 5.4 %. In addition, the main flow increases when the flow through the perforation increases, and this leads to an increase in the average of wall shear stress.