The ceramic composite with different proportions of clay and silica was prepared with a grain size of 70 μm and the weight percentage was selected for four groups (clayx silica100-x) were x q15, 25, 30 and 50. In this manuscript, for each pressured sample, a sintering procedure was carried out for 3 hours under static air and at various sintering temperatures (1000, 1100, 1200, 1400)°C. After sintering, the density, porosity, water absorption, compression strength and thermal conductivity were measured. The best results were obtained using a mixture of 15% clay and 85% silica which were sintering at 1400°C for three hours under air.
Conjugate heat transfer has significant implications on heat transfer characteristics, particularly in thick wall applications and small diameter pipes. In this study, a three-dimensional numerical investigation was carried out using commercial CFD software “ANSYS FLUENT” to study the influence of conjugate heat transfer of laminar flow in mini channels at constant heat flux wall conditions. Two parameters were studied and analyzed: the wall thickness and thermal conductivity and their effect on heat transfer characteristics such as temperature profile and Nusselt number. Thermal conductivity of (0.25, 10, 202, and 387) W/m2C and wall thickness of (1, 5, and 50) mm were used for a channel of (1*2) mm cross
... Show MoreThis article deals with the impact of including transverse ribs within the absorber tube of the concentrated linear Fresnel collector (CLFRC) system with a secondary compound parabolic collector (CPC) on thermal and flow performance coefficients. The enhancement rates of heat transfer due to varying governing parameters were compared and analyzed parametrically at Reynolds numbers in the range 5,000–13,000, employing water as the heat transfer fluid. Simulations were performed to solve the governing equations using the finite volume method (FVM) under various boundary conditions. For all Reynolds numbers, the average Nusselt number in the circular tube in the CLFRC system with ribs was found to be larger than that of the plain abs
... Show MoreNewly acid hydrazide was synthesized from ethyl 2-(2,3-dimethoxyphenoxy) acetate (2), which is cyclized to the corresponding 4-amino-1,2,4-triazole (3). Five newly azo derivatives (4a-e) were synthesized from this 1,2,4-triazole by converting the amine group to diazonium salt then reacted with various substituent phenol,as well three newly imine derivatives (5a-c) were synthesized from reacting the amine group of compound (3) with three aryl aldehyde. The thermal electro conductivity of these compounds was tested at 30, 50, 75 and 100 áµ’C. compound 4a showed interesting electro conductivity at 75áµ’C as well 5a at 75áµ’C while 5b showed significant conductivity at 100 áµ’C
Solar photovoltaic (PV) has many environmental benefits and it is considered to be a practical alternative to traditional energy generation. The electrical conversion efficiency of such systems is inherently limited due to the relatively high thermal resistance of the PV components. An approach for intensifying electrical and thermal production of air-type photovoltaic thermal (PVT) systems via applying a combination of fins and surface zigzags was proposed in this paper. This research study aims to apply three performance enhancers: case B, including internal fins; case C, back surface zigzags; and case D, combinations of fins and surface zigzags; whereas the baseline smooth duct rep
Four new copolymers were synthesized from reaction of bis acid monomer 3-((4-carboxyphenyl) diazenyl)-5-chloro-2-hydroxybenzoic acid with five diacidhydrazide in presence of poly phosphoric acid. The resulted monomers and copolymers have been characterized by FT-IR, 1H-NMR, 13C-NMR spectroscopy as well as EIMs technique. The number averages of molecular weights of the copolymers are between 4822 and 9144, and their polydispersity indexes are between 1.02 and 2.15. All the copolymers show good thermal stability with the temperatures higher than 305.86 C when losing 10% weight under nitrogen. The cyclic voltammetry (CV) measurement and the electrochemical band gaps (Eg) of these copolymers are found below 2.00 ev.
Wellbore stability is considered as one of the most challenges during drilling wells due to the
reactivity of shale with drilling fluids. During drilling wells in North Rumaila, Tanuma shale is
represented as one of the most abnormal formations. Sloughing, caving, and cementing problems
as a result of the drilling fluid interaction with the formation are considered as the most important
problem during drilling wells. In this study, an attempt to solve this problem was done, by
improving the shale stability by adding additives to the drilling fluid. Water-based mud (WBM)
and polymer mud were used with different additives. Three concentrations 0.5, 1, 5 and 10 wt. %
for five types of additives (CaCl2, NaCl, Na2S
Nanoparticles (NPs) have unique capabilities that make them an eye-opener opportunity for the upstream oil industry. Their nano-size allows them to flow within reservoir rocks without the fear of retention between micro-sized pores. Incorporating NPs with drilling and completion fluids has proved to be an effective additive that improves various properties such as mud rheology, filtration, thermal conductivity, and wellbore stability. However, the biodegradability of drilling fluid chemicals is becoming a global issue as the discharged wetted cuttings raise toxicity concerns and environmental hazards. Therefore, it is urged to utilize chemicals that tend to break down and susceptible to biodegradation. This research presents the pra
... Show MoreTo reduce the effects of discharging heated water disposed into a river flow by a single thermal source, two parameters were changed to get the minimum effect using optimization. The first parameter is to distribute the total flow of the heated water between two disposal points (double source) instead of one and the second is to change the distance between these two points. In order to achieve the solution, a two dimensional numerical model was developed to simulate and predict the changes in temperature distribution in the river due to disposal of the heated water using these two points of disposal.
MATLAB-7 software was used to build a program that could solve the governing partial equations of thermal pollution in rivers by using t