Preferred Language
Articles
/
alkej-631
Free Convective Heat Transfer with Different Sections Lengths Placed at the Exit of a Vertical Circular Tube subjected to a Constant Heat Flux
...Show More Authors

A free convective heat transfer from the inside surface of a uniformly heated vertical circular tube has been experimentally investigated under a constant wall heat flux boundary condition for laminar air flow in the ranges of RaL from 6.9108 to 5109. The effect of the different sections (restrictions) lengths placed at the exit of the heated tube on the surface temperature distribution, the local and average heat transfer coefficients were examined. The experimental apparatus consists of aluminum circular tube with 900 mm length and 30 mm inside diameter (L/D=30). The exit sections (restrictions) were included circular tubes having the same inside diameter as the heated tube but with different lengths of 600 mm (L/D=20), 900 mm (L/D=30), 1200 mm (L/D=40), 1500 mm (L/D=50), and 1800 mm (L/D=60). It was found that the surface temperature along the tube axial distance would be higher for restriction with length of 1800 mm (L/D=60) and it would be smaller for the restriction with length of 1200 mm (L/D=40). The results show that the local Nux and average Nusselt number were higher values for the restriction with length of 1200 mm (L/D=40) and smaller values for the restriction with length of 1800 mm (L/D=60). The results were correlated with empirical equations and presented as Logagainst Log for each case investigated and a general empirical equation was proposed for all cases.

 

View Publication Preview PDF
Quick Preview PDF
Publication Date
Thu Feb 01 2018
Journal Name
Applied Energy
Solidification enhancement of PCM in a triplex-tube thermal energy storage system with nanoparticles and fins
...Show More Authors

View Publication
Scopus (289)
Crossref (271)
Scopus Clarivate Crossref
Publication Date
Tue Jun 01 2021
Journal Name
Journal Of Engineering
Experimental Investigation of a Single Basin -Single Slope Solar Still Coupled with Evacuated Tube Solar Collector
...Show More Authors

This work is an experimental investigation for single basin-single slope solar still coupled with an evacuated tube solar collector. The work is carried out under the climatic conditions of Baghdad city (33.2456º North and East latitude, 44.3337º longitude) through certain days of the months of the year 2019 to study the impact of using evacuated tube solar collector on the daily productivity and efficiency under the outdoors climatic conditions. It was found that using the evacuated tube solar collector increase daily productivity from 2.175 kg/  to 2.95 kg/ for 9 hours (35.63 %) for clear days, also an enhancement about 10.97 % in daily efficiency.

View Publication Preview PDF
Crossref (3)
Crossref
Publication Date
Fri Jan 01 2016
Journal Name
International Journal Of Innovative Research In Science, Engineering And Technolog
Effect Of heat Treatment On The Optical Properties Of CuInSe2 Thin Films
...Show More Authors

CuInSe2(CIS) thin films have been prepared by use vacuum thermal evaporation technique, of thickness750 nm with rate of deposition 1.8±0.1 nm/sec on glass substrate at room temperature and pressure (10-5) mbar. Heat treatment has been carried out in the range (400-600) K for all samples. The optical properties of the CIS thin films are been studied such as (absorption coefficient, refractive index, extinction coefficient, real and imaginary dielectric constant) by determined using Measurement absorption and transmission spectra. Results showed that through the optical constants we can make to control it are wide applications as an optoelectronic devices and photovoltaic applications.

View Publication
Publication Date
Thu Jan 07 2016
Journal Name
International Journal Of Innovative Research In Science, Engineering And Technology
Effect Of heat Treatment On The Optical Properties Of CuInSe2 Thin Films
...Show More Authors

CuInSe2 (CIS)thin films have been prepared by use vacuum thermal evaporation technique, of 750 nm thickness, with rate of deposition 1.8±0.1 nm/sec on glass substrate at room temperature and pressure (10-5) mbar. Heat treatment has been carried out in the range (400-600) K for all samples. The optical properties of the CIS thin films are been studied such as (absorption coefficient, refractive index, extinction coefficient, real and imaginary dielectric constant)by determined using Measurement absorption and transmission spectra. Results showed that through the optical constants we can made to control it is wide applications as an optoelectronic devices and photovoltaic applications.

Preview PDF
Publication Date
Sat Jan 01 2011
Journal Name
Journal Of Engineering
MIXED CONVECTION PHENOMINA AFFECTED BY RADIATION IN A HORIZONTAL RECTANGULAR DUCT WITH COCENTRIC AND ECCENTRIC CIRCULAR CORE
...Show More Authors

The numerical investigation has been performed to study the radiation affected steady state laminar mixed convection induced by a hot inner varied positions circular core in a horizontal rectangular channel for a fully developed flow. To examine the effects of thermal radiation on thermo fluid dynamics behavior in the eccentric geometry channel, the generalized body fitted co-ordinate system is introduced while the finite difference method is used for solving the radiative transport equation. The governing equations which used are continuity, momentum and energy equations. These equations are normalized and solved using the Vorticity-Stream function. After validating numerical results for the case without radiation, the detailed radiatio

... Show More
View Publication Preview PDF
Crossref
Publication Date
Sat Jan 01 2011
Journal Name
Journal Of Engineering
MIXED CONVECTION PHENOMINA AFFECTED BY RADIATION IN A HORIZONTAL RECTANGULAR DUCT WITH COCENTRIC AND ECCENTRIC CIRCULAR CORE
...Show More Authors

The numerical investigation has been performed to study the radiation affected steady state laminar mixed convection induced by a hot inner varied positions circular core in a horizontal rectangular channel for a fully developed flow. To examine the effects of thermal radiation on thermo fluid dynamics behavior in the eccentric geometry channel, the generalized body fitted co-ordinate system is introduced while the finite difference method is used for solving the radiative transport equation. The governing equations which used are continuity, momentum and energy equations. These equations are normalized and solved using the Vorticity-Stream function. After validating numerical results for the case without radiation, the detailed rad

... Show More
Crossref
Publication Date
Sun May 02 2021
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Value at risk simulation in a fixed return stock portfolio using the Monte Carlo simulation model The concept of a bond portfolio
...Show More Authors

This research aims to predict the value of the maximum daily loss that the fixed-return securities portfolio may suffer in Qatar National Bank - Syria, and for this purpose data were collected for risk factors that affect the value of the portfolio represented by the time structure of interest rates in the United States of America over the extended period Between 2017 and 2018, in addition to data related to the composition of the bonds portfolio of Qatar National Bank of Syria in 2017, And then employing Monte Carlo simulation models to predict the maximum loss that may be exposed to this portfolio in the future. The results of the Monte Carlo simulation showed the possibility of decreasing the value at risk in the future due to the dec

... Show More
View Publication Preview PDF
Publication Date
Sun Feb 01 2015
Journal Name
Journal Of Engineering
Impact Analysis of Reinforced Concrete Columns with Side Openings Subjected to Eccentric Axial Loads
...Show More Authors

In this research the behavior of reinforced concrete columns with large side openings under impact loads was studied. The overall cross sectional dimensions of the column specimens used in this research were (500*1400) mm with total height of (14000) mm. The dimensions of side openings were (600*2000) mm. The column was reinforced with (20) mm diameter in longitudinal direction, while (12) mm ties were used in the transverse direction. The effect of eccentric impact loads on the horizontal and vertical displacement for this column was studied.                              &

... Show More
View Publication Preview PDF
Publication Date
Mon Feb 02 2015
Journal Name
Journal Of Engineering, University Of Baghdad
'Impact Analysis of Reinforced Concrete Columns with Side Openings Subjected to Eccentric Axial Loads
...Show More Authors

View Publication
Publication Date
Mon Dec 01 2014
Journal Name
Advances In Structural Engineering
CFRP Strengthening of RC Beams with Multiple Openings Subjected to Static and Impact Loads
...Show More Authors

The provision of openings in serviceable reinforced concrete beams may result in a substantial decline in the beam's capacity and integrity, indicating the necessity of opening strengthening. The present study investigates the experimental response of reinforced concrete T-beams with multiple web-strengthened openings disposed in shear span to static and impact loads. Fourteen RC T-beams were tested in two groups, each of seven beams. The first group was tested under static loading up to failure, while the second group was tested under repeated impact loading until the width of shear cracks reached 0.3 mm. The residual static strengths of the beams subjected to impact loading were then determined. The test variables considered were

... Show More
Crossref (11)
Crossref