eng
Shiraz University
Iranian Journal of Science and Technology Transactions of Mechanical Engineering
2228-6187
2013-04-01
37
1
63
70
10.22099/ijstm.2013.1466
1466
مقاله پژوهشی
EXPERIMENTAL AND NUMERICAL STUDY OF A TURBULENT AXISYMMETRIC
JET IMPINGING ONTO A CIRCULAR CYLINDER IN OFFSET
AND NON-OFFSET SITUATIONS
In this study, an experimental and numerical analysis is done to study the flowcharacteristics of an offset and non-offset axisymmetric jet impingement on a circular cylinder.The purpose of this study is investigation of the behavior of the cutting gas jets and finding theoptimum distance between nozzle and cylinder to achieve maximum cutting performance. Finitevolume approach is used to solve the governing equations for a turbulent, incompressible jetnumerically. According to the literature the suitable turbulence model for this purpose is realizablek-ε. Velocity and pressure fields around the cylinder and pressure and shear stress distribution onthe cylinder surface are determined for various cases. Also, some experiments are done to validaterepeatability of experiments and numerical results. Comparisons between numerical results andexperimental measurements validate the accuracy of numerical results. Also, results show that ifthe horizontal distance between the nozzle outlet and the stagnation point of cylinder is 2.5D, theshear stress on the cylinder surface has maximum value. Therefore in this situation jet has amaximum performance in cutting procedure.
https://ijstm.shirazu.ac.ir/article_1466_809eaf8b5ff3419a3f2810aae4c21a00.pdf
impinging jet
axisymmetric jet
offset/non-offset impinging
circular cylinder
eng
Shiraz University
Iranian Journal of Science and Technology Transactions of Mechanical Engineering
2228-6187
2013-04-01
37
1
71
75
10.22099/ijstm.2013.1467
1467
مقاله پژوهشی
SIMULATION OF LAMINAR MIXED CONVECTION RECESS FLOW
COMBINED WITH RADIATION HEAT TRANSFER
In the current work, two-dimensional simulations are presented for incompressiblelaminar mixed convection flow of a radiating gas over a recess including two backward andforward facing steps in a vertical duct. The continuity, momentum and energy equations for fluidflow are solved by the computational fluid dynamic (CFD) techniques. The fluid is treated as agray, absorbing, emitting and scattering medium. For computation of the radiative term in theenergy equation, the radiative transfer equation (RTE) is solved numerically by the discreteordinates method (DOM). The effects of Grashof number, radiation-conduction parameter andoptical thickness on heat transfer behavior of the system are studied.
https://ijstm.shirazu.ac.ir/article_1467_7acf1baec66d5c04fc122ee8b37e4ea0.pdf
Laminar mixed convection flow
recess
radiation
DOM
eng
Shiraz University
Iranian Journal of Science and Technology Transactions of Mechanical Engineering
2228-6187
2013-04-01
37
1
77
82
10.22099/ijstm.2013.1468
1468
مقاله پژوهشی
VIBRATION CHARACTERISTICS OF CONTINUOUSLY
VARIABLE TRANSMISSION PUSH BELTS
A CVT push-belt, composed of 12 layers of bands and a number of segments, ismodeled for vibration analysis. Predefined compression and tension loads are applied to segmentsand bands respectively. Continuous and discrete beams composed of segments are used toinvestigate contact properties between segments. Three models of band contacts have beenestablished based on complexity and various modeling approaches in ABAQUS. Contacts betweenbands are modeled by a frictionless contact between shell elements tied together in the first modeland in the second model. To improve the accuracy, a composite shell with special interface layersis utilized as third model. By using the segment models, it has been concluded that a group ofsegments can be considered as a continuous beam at high compression loads and as individualrigid masses in low compression loads. The results of composite shell model show betterprediction of the vibration properties of bands pack model. Separate cases of loading areconsidered for tension and compression spans.
https://ijstm.shirazu.ac.ir/article_1468_ce5b9cded07edc5c7f603fec85e9b8c6.pdf
CVT
push-belt
vibration
finite element
contact modeling