Kadhum Audaa Jehhef
@mtu.edu.iq
university of technology
Central Technical University
RESEARCH INTERESTS
heat transfer
Scopus Publications
Scopus Publications
Kadhum Jehhef, Musaab Rasheed, and Mohamed Siba
National Library of Serbia
The present numerical study aims to present the effect of using a titled oscillating thin plate with different angles of inclination on the Al2O3-water nanofluid flow and heat transfer performance. The subsequent work establishes methods for forming fluid-structure interactions by impact of Al2O3-water nanofluid at 0.1-1.0 vol. % volume fraction upon the thin plate using COMSOL Multiphysics 5.4. The turbulent model is solved using the (k-?) model and the assembly of the flow around the thin plate obstacle has been confirmed at Reynolds number of Re=4?104. It exemplifies how Nanofluid flow interaction can distort structures. The current study donates to the study of the turbulent, two-dimensional, stationary and incompressible flow around an oscillating thin plate that has inclined angles with upstream and downstream that mounted inside a horizontal channel. The numerical study includes investigation the effect of five inclination angles of the thin plate as (30, 60, 90, 120 and 150?) on the pressure, velocity, and temperatures contours of the Al2O3-water nanofluid. Also, the study presented the profile of the drag and left force of the thin plate that causing by the fluid flow. The results showed that the occurrence of a titled oscillating thin plate inside the flow direction leads to an increase pressure drop, von mises deformation stress, x-displacement and drag force fields and the Nusselt number. Where the pressure increased from 2.61?103 to 6.21?103 pa, the von mises stress increased from 4.43?106 to 1.78?107 N/m, and the X-displacement increased from 1.6 to 5.5 mm when increasing the plate angle from 30 to 90?.
Kadhum Audaa Jehhef, Faris Ali Badawy, and Mohamed Abed Al Abas Siba
AIP Publishing
Musaab K. Rashed, Kadhum Audaa Jehhef, and Faris Ali Badawy
Walter de Gruyter GmbH
Abstract This paper presents a numerical study of heat transfer through a downstream annulus using water as the working fluid within the laminar flow region. The annulus consisted of an outer twisted square duct and an inner circular pipe. A three-dimensional formulation was used to solve the Navier-Stokes equations numerically for the laminar flow system with a low Reynolds number. Three parameters were used in the numerical simulation: the length of the twisted square (a: 6.6, 8.2 10.2, 12.6 mm) the inner diameter of the inner circular pipe (d: 19, 21, 23 and 25 mm); and the twist angle (θ: 0° (smooth), 45°, 60°, and 90°). Numerical calculations were conducted on sixteen twisted square duct heat exchangers, with water flowing within a Reynolds number range of 220 – 1100. The results were illustrated as a profile of the thermal enhancement factor, the friction factor and the Nusselt number. The results show that the twisted outer duct of the heat exchanger can create a swirl flow along the length of the heat exchanger. It also caused a boundary layer separation-reattachment on the wall of the inner pipe. Moreover, an increase in the twist angle increased the Nusselt number by 20 %, and the friction factor was also increased as the annular gap of the heat exchanger decreased.
K.A. Jehhef, F.A. Badawy, and A.A. Hussein
Walter de Gruyter GmbH
Abstract This paper aims to investigate the mixed convection between two parallel plates of a vertical channel, in the presence of a triangular rib. The non-stationary Navier-Stokes equations were solved numerically in a two-dimensional formulation for the low Reynolds number for the laminar air flow regime. Six triangular ribs heat-generating elements were located equidistantly on the heated wall. The ratio of the ribs to the channel width is varied (h / H = 0.1, 0.2, 0.3 and 0.4) to study the effect of ribs height effects, the ratio of the channel width to the ribs height is fixed constant at (H / w = 2) and the ratio of the channel height to the ribs pitch is fixed at (W/p=10). The influence of the Reynolds number that ranged from 68 to 340 and the Grashof number that ranged from 6.6 ×103 to 2.6 ×104 as well as the Richardson number chosen (1.4, 0.7, 0.4 and 0.2) is studied. The numerical results are summarized and presented as the profile of the Nusselt number, the coefficient of friction, and the thermal enhancement factor. The contribution of forced and free convection to the total heat transfer is analyzed. Similar and distinctive features of the behavior of the local and averaged heat transfer with the variation of thermal gas dynamic and geometric parameters are investigated in this paper. The results showed that the Nusselt number and friction factor increased by using the attached triangular ribs, especially when using the downstream ribs. Also, the results revealed that the Nusselt number increased by increasing the ratio of the ribs to the channel width.
Kadhum Audaa Jehhef, , Ali Jalal Ali, and
Prof. Marin Drinov Publishing House of BAS (Bulgarian Academy of Sciences)
In order to fully understand the interaction between the Abdominal Aortic Aneurysms (AAAs) and the arterial bifurcations interface it is important to attain more detailed information on blood hemodynamics stresses by using an accurate and real model of the vascular system of the human. In this study, a computer simulation, which integrates dinically acquired of 73-year-old male patient with saccular AAA MR angiograms image is considered. The numerical predictions for 2D of two models (with and without saccular AAA) – axisymmetric, rigid wall Newtonian and non-Newtonian Carreau blood model are presented. The finite volume method performed by ANSYS-Fluent Package was used to model this problem. The blood hemodynamics is considered as steady state condition in two values of Reynolds numbers of laminar flow condition. Blood hemodynamics is calculated for an improved set of dimensionless values pointer parameters include the pressure dimensionless, dimensionless Wall Shear Stress (WSS) and flow velocity. The results show that at the turbulent flow, velocity is with highest fluctuation profile and generate some vortices near the inner wall of AAA. The highest WSS levels are obtained downstream of AAA and at bifurcation apex. The presence of AAA in flow path will increase blood velocity of the distal by 35% for laminar and about 42% for turbulent. Finally, the velocity profile was compared with previous literature and give good agreement at the same computational condition.
Salah H. Abid AUN, Safaa A. GHADHBAN, and Kadhum A. JEHHEF
Journal of Thermal Engineering
Safaa A. Ghadhban, Salah Haji Abid Aun, and Kadhum Audaa Jehhef
IOP Publishing
Shaalan Ghanam Afluq, Mohamed Abed Al Abas Siba, and Kadhum Audaa Jehhef
IOP Publishing
Kadhum Audaa Jehhef, Salah Haji Abid Aun, and Mohamed Abed Al Abas Siba
IOP Publishing
Kadhum Audaa Jehhef, Mohamed Abedle Sattar Khdair, and Kareem Jabbar Thajeel
IOP Publishing
The effects caused by convection and radiation heat transfer on the distribution of temperature, airflow and heat transfer in a greenhouse containing a heated solid block are studied numerically. Differential governing equations of the system are analyzed by utilized the finite volume method and the coupling of pressure-velocity is handled by the algorithm of SIMPLER. The systems algebraic equations are resolved by the conjugated of the gradient method. The greenhouse is supposed of an aspect ratio of A = 1.5, and the numerical results are presented in terms of streamlines, isotherms and Nusselt number for the range of Rayleigh numbers between 103 and 106. For the case of inlet airflow, the mixed convection of the airflow of in a greenhouse formed by two walls lateral and a roof with two symmetrical slopes were studied. The heating conditions of the walls for the greenhouse was taken as (Tc for the floor and Tf for the roof, with Tc> Tf), with openings of the cold air inlet is left-walled and the outlet is so the symmetry of right walls. The Prandtl number is set at 0.702 (for the case of air). Several situations have been considered for Rayleigh number and solid block height at fixed Reynolds number at Re = 100. The results showed that the Rayleigh number has important effect on the performance of the flow and thermal structure. Also, the isotherms and current lines is effected by varying the solid block height. In addition the local and medium Nusselt number along the hot wall increased with increasing the Rayleigh number and solid block height.
Kadhum Audaa Jehhef, Rehab H. Khanjar, and M A Siba
IOP Publishing
K A Jehhef and N J Yasin
IOP Publishing
Nabil J. Yasin, Kadhum A. Jehhef, and Zahraa A. Mohsen
IOP Publishing