This paper aims to study the effect of circular Y-shaped fin arrangement to improve the low thermal response rates of a double-tube heat exchanger containing Paraffin phase change material (PCM). ANSYS software is employed to perform the computational fluid dynamic (CFD) simulations of the heat exchanger, including fluid flow, heat transfer, and the phase change process. The optimum state of the fin configuration is derived through sensitivity analysis by evaluating the geometrical parameters of the Y-shaped fin. For the same height of the fins (10 mm), the solidification time is reduced by almost 22%, and the discharging rate is enhanced by almost 26% using Y-shaped fins compared with the straight fins. The results demonstrate that the solidification time is inversely proportional to the fin's length. The heat release rate for the case with the longest fins (stem length of 10 mm) is 39 W, almost 2.8 times higher than that with the fins' stem length of 5 mm. The case with the tributary's angle of 22.5o solidified in 55 min, faster than the other studied angles. Increasing the number of fins significantly affects the solidification time and discharging rate. By increasing the number of fins from 3 to 9, the heat transfer rate improves by 194%. The advantages of circular Y-shaped fins are well known in heat transfer applications and therefore are characterized toward higher performance in this study for the first time during the solidification process.
Los enunciados interrogativos desempeñan un papel de sumo interés en el habla del ser humano en todo el mundo, además de la gran importancia que desempeñan sus distintos enunciados y partículas en abreviar las oraciones y hacer llegar a nuestro interlocutor nuestra intención con pocas palabras, por eso a través de esta investigación vamos a enfocar la luz sobre uno de sus tipos fundamentales "los enunciados interrogativos directos", a través de un estudio morfológico contrastivo entre el árabe y el español, este fue el principal motivo para elegir este tema.
A pesar de que los enunciados interrogativos directos aparentemente no ofrecen mucha dificultad, pero dominar a dicho tipo de enunciados con
... Show MoreEl moviemiento literario español de posguerra ha visto un cambio muy transcendental al nivel de plantear los temas y la técnica de formar el genero literario ,de forma que la poesίa ha ocupado un espacio muy significativo en ello ,dado que los poetas buscaban metedos creativos para atraer el público , siguiendo senedores que pudieran afectar de forma u otra en las mentes y sentimientos.
En esta dirección ,Gabriel Celaya se resalta como voz que ha traspasado el ánimo de dos promociones genericas que son la de 27 y la de 36, por lo cual podίa conllevar unas asencias muy basicas de la poesίa española que envuelven la precisión clásica y prodencia contemporanea, con
... Show MoreLa vida literaria española ha visto unos cambios muy importantes después de la guerra civil (1936-1939), ya porque la sociedad se vio afectada mayoritariamente, de modo que la literatura de posguerra se ha concentrado en remontar el ánimo social español.
Blas de Otero (1916-1979) (1) ha representado una señal muy singular e importante del movimiento poético de los años cuarenta y cincuenta. La poesía de Otero apuntaba el camino social realista de lo sufría su sociedad, en cuanto la dirección general de la literatura española se dirigía hacia lo aceptable en el entorno social.
El localismo en la poesía de Blas de Otero forma un grito social peculiar, de modo que se nota el acercamie
... Show MoreLos enunciados interrogativos desempeñan un papel de sumo interés en el habla del ser humano en todo el mundo, además de la gran importancia que desempeñan sus distintos enunciados y partículas en abreviar las oraciones y hacer llegar a nuestro interlocutor nuestra intención con pocas palabras, por eso a través de esta investigación vamos a enfocar la luz sobre uno de sus tipos fundamentales "los enunciados interrogativos directos", a través de un estudio morfológico contrastivo entre el árabe y el español, este fue el principal motivo para elegir este tema.
A pesar de que los enunciados interrogativos directos aparentemente no ofrecen mucha dificultad, pero dominar a dicho tipo de enunciados con todas sus divisiones, sus
Sustainability is a major demand and need pursued by cities in all areas of life due to the environmental, social and economic gains they provide, especially in the field of city planning and urban renewal projects that aim to integrate the past, present and future.
The research aims to evaluate the Haifa Street renewal project, and Al-Shawaka district, one of the Baghdad districts located next to Al-Karkh, was elected by comparing the sustainability indicators of urban renewal with the reality of the situation through a field survey and questionnaire form and focusing on the social and economic impacts and environmental for the project on the study area. To reach the most important conclusions and recommendations
... Show MoreBackground: The most widely used material for fabrication of denture base is poly methyl methacrylate, despite its popularity, the main problems associated with it as a denture base material are poor strength particularly under fatigue failure inside the patient mouth, impact failure outside the patient mouth, which are the main causes for fracture of denture, several studies was done to increase mechanical properties of denture base. The present study was conducted to evaluate and compare the effect of addition single walled carbon nanotubes in different concentrations to polymethyl methacrylate on some mechanical properties (surface hardness, surface roughness, impact strength and transverse strength). Materials and methods: Forty eight
... Show MoreThe present paper deals with studying the effect of electrical discharge machining (EDM) and shot blast peening parameters on work piece fatigue lives using copper and graphite electrodes. Response surface methodology (RSM) and the design of experiment (DOE) were used to plan and design the experimental work matrices for two EDM groups of experiments using kerosene dielectric alone, while the second was treated by the shot blast peening processes after EDM machining. To verify the experimental results, the analysis of variance (ANOVA) was used to predict the EDM models for high carbon high chromium AISI D2 die steel. The work piece fatigue lives in terms of safety factors after EDM models were developed by FEM using ANSY
... Show MoreA study of the effects of the discharge (sputtering) currents (60-75 mA) and the thickness of copper target (0.037, 0.055 and 0.085 mm) on the prepared samples was performed. These samples were deposited with pure copper on a glass substrate using dc magnetron sputtering with a magnetic flux density of 150 gauss at the center. The effects of these two parameters were studied on the height, diameter, and size of the deposition copper grains as well as the roughness of surface samples using atomic force microscopy (AFM).The results of this study showed that it is possible to control the specifications of copper grains by changing the discharge currents and the thickness of the target material. The increase in discharge curre
... Show MoreAutonomous systems are these systems which power themselves from the available ambient energies in addition to their duties. In the next few years, autonomous systems will pervade society and they will find their ways into different applications related to health, security, comfort and entertainment. Piezoelectric harvesters are possible energy converters which can be used to convert the available ambient vibration energy into electrical energy. In this contribution, an energy harvesting cantilever array with magnetic tuning including three piezoelectric bimorphs is investigated theoretically and experimentally. Other than harvester designs proposed before, this array is easy to manufacture and insensitive to manufacturi
... Show MoreThis paper presents the first data for bremsstrahlung buildup factor (BBUF) produced by the complete absorption of Y-91 beta particles in different materials via the Monte Carlo simulation method. The bremsstrahlung buildup factors were computed for different thicknesses of water, concrete, aluminum, tin and lead. A single relation between the bremsstrahlung buildup factor BBUF with both the atomic number Z and thickness X of the shielding material has been suggested.