Numerical Investigation on Slot air Jet impingement Heat Transfer between Horizontal Concentric Circular Cylinders

سال انتشار: 1394
نوع سند: مقاله ژورنالی
زبان: انگلیسی
مشاهده: 400

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شناسه ملی سند علمی:

JR_JACM-1-2_004

تاریخ نمایه سازی: 9 خرداد 1396

چکیده مقاله:

Numerical study has been carried out for slot air jet impingement cooling of horizontal concentric circular cylinders. The slot air jet is situated at the symmetry line of a horizontal cylinder along the gravity vector and impinges to the bottom of the outer cylinder which is designated as θ=0°. The outer cylinder is partially opened at the top with width of W=30mm and is kept at constant temperature T= 62°C. Inner cylinder which is a part of the slot jet structure is chosen to be insulated. The effects of jet Reynoldsnumber in the range of 100≤ Rej ≤1000 and the ratio of spacing between nozzle and outer cylinder surface to the jet width for H=4.2 and H=12.5 on the local and average Nusselt numbers are examined. In the numerical study, FLUENT CFD package is used and validated by comparing the results with the experimental data at the same Reynolds number. It is observed that the maximum Nusselt number occurs at the stagnation point at (θ=0°) and the local heat transfer coefficient decrease on the circumference of thecylinder with increase of θ as a result of thermal boundary layer thickness growth. Also results show that the local and average heat transfer coefficients are raised by increasing the jet Reynolds number and bydecreasing the nozzle-to-surface spacing

نویسندگان

Arash Azimi

Department of Mechanical and Aerospace Engineering, Science and Research Branch, Islamic Azad University, Tehran Tehran, 14778-93855, Iran,

Mehdi Ashjaee

Department of Mechanical Engineering, University of Tehran Tehran, Karegar street, Iran,

Morteza Khayat

Department of Mechanical and Aerospace Engineering, Science and Research Branch, Islamic Azad University, Tehran Tehran, 14778-93855, Iran,