The present work presents a new experimental study of the enhancement of turbulent
convection heat transfer inside tubes for combined thermal and hydrodynamic entry length of one
popular “turbulator” (twisted tape with width slightly less than internal tube diameter) inserted for
fire tube boilers. Cylindrical combustion chamber was used to burn (1.6 to 7kg/h) fuel oil #2 to
deliver hot gases with ranges of Reynolds number (10500 to 21700), and (11400 to 24150) for both
empty and inserted tube respectively.A uniform wall temperature technique was used by keeping
approximately constant water temperature difference (25ºC) between inlet and exit cooling water in
parallel flow shell and tube heat exchanger. The test tube consisted of smooth carbon steel tube of
(2400mm) long and (52mm) internal diameter. This test tube instrumented to derive local heat
transfer coefficient and local flue gasses static pressure.The experimental results show that for the
same fuel consumption, twisted tape insert with (H/D = 11.15) enhanced the mean Nusselt number
in (75.2%), (68.8%), (49.8%), (40.3%), and (16.7%) for fuel consumption (7kg/h), (6.16kg/h),
(4.5kg/h), (3.24kg/h), and (1.6kg/h) respectively.A set of empirical correlations that permit the
evaluation of the mean Nusselt number (for developing and fully developed region), and average
Nusselt number (for developed region) for empty and inserted tube are generated for engineering
applications.
Three-dimensional cavity was investigated numerical in the current study filled with porous medium from a saturated fluid. The problem configuration consists of two insulated bottom and right wall and left vertical wall maintained at constant temperatures at variable locations, using two discretized heaters. The porous cavity fluid motion was represented by the momentum equation generalized model. The present investigation thermophysical parameters included the local thermal equilibrium condition. The isotherms and streamlines was used to examine energy transport and momentum. The meaning of changing parameters on the established average Nusselt number, temperature and velocity distribution are highlighted and discussed.
Arabic language , like any other living languages grow and evolve ; social phenomenon
it is subject to the law of life ; therefore resemble organism also touted as the most eloquent
language and the ability to meet the needs of people in every time and place.
The contemplation of the verses of the Koran reveals a lot of means of expression
leading to the grammatical meaning of the social.
I have tried in this research that investigated the social meanings through the phenomena
of deletion and delivery delays and capture semantic landing through the meanings that lead
to psychological persuasion to comply with the orders after the rights of the divine in which
social directives.
It remains the greatest mystery o
Asthma is a chronic inflammatory disease that involves the narrowing of the lung airways and excessive mucus production. Resveratrol (RES), a polyphenolic stilbene, is known to control asthmatic attacks via different molecular mechanisms. However, no studies have examined the effect of resveratrol on the microbiome in the ovalbumin (OVA)-induced asthma mouse model. In this study, we induced asthma in BALB/c mice by injecting OVA followed by 7 days treatment with RES. Plethysmography showed that the expiratory resistance in the lung tissue was significantly reduced in the RES treated group, while mean volume, peak expiratory flow, and frequency of respiration was increased. Histopathol
Chilled ceilings systems offer potential for overall capital savings. The main aim of the present research is to investigate the thermal performance of the indirect contact closed circuit cooling tower, ICCCCT used with chilled ceiling, to gain a deeper knowledge in this important field of engineering which has been traditionally used in various industrial & HVAC systems. To achieve this study, experimental work were implemented for the ICCCCT use with chilled ceiling. In this study the thermal performances of closed wet cooling tower use with chilled ceiling is experimentally and theoretically investigated. Different experimental tests were conducted by varying the controlling parameters to investigate their effects
... Show MoreThe experiment was carried out in the green house of botanical garden belong to Department of Biology/College of Education for Pure Science- Ibn–al- Haitham/University of Baghdad, for the growth season 2015 using plastic pots. The experiment aimed to study the effect of two concentrations of sodium chloride (50, 100) mM.L-1 in addition to the control and four concentrations of kinetin (25, 50, 75, 100) mg.L-1 in addition to the control and the influence of application and non application of fertilizlizer NPKZn in the level 160 kg.h1- and their interactions on some growth parameters (fresh weight for both root and vegetative part, dry weight for leaves , value of secondary productivity, biomass duration for vegetative part and dry weight f
... Show MoreThis paper aims to investigate the flexural behavior of reinforced concrete beams considering fire resistance by adding Lightweight Expanded Clay Aggregates (LECA) to the concrete mix as partial coarse aggregate replacement. LECA is a type of porous clay with a uniform pore structure with fine, closed cells and hard, tightly sintered skin. The experimental work comprised four reinforced self-compacted concrete beams. All the specimens were identical in their geometrical layout of 1600×240×200 mm, reinforcement details, and support condition (simply supported). For all the beams, the main reinforcement was provided by two bars, each having a diameter of 12 mm, while a bar of 6 mm diameter was employed for the top and shear reinforc
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