Numerical Heat Transfer Correlation for Array of Hot-Air Jets Impinging on 3-Dimensional Concave Surface

2005 ◽  
Vol 42 (3) ◽  
pp. 665-670 ◽  
Author(s):  
Mathieu Fregeau ◽  
F. Saeed ◽  
I. Paraschivoiu
Keyword(s):  
Heat Transfer ◽  
Concave Surface ◽  
Heat Transfer Correlation ◽  
3 Dimensional ◽  
Numerical Heat Transfer ◽  
Air Jets ◽  
Hot Air

Simulation of Heat Transfer From Hot-Air Jets Impinging a Three-Dimensional Concave Surface

2009 ◽  
Vol 46 (2) ◽  
pp. 721-726 ◽  
Author(s):  
Mathieu Fregeau ◽  
Mohammad Gabr ◽  
Ion Paraschivoiu ◽  
Farooq Saeed
Keyword(s):  
Heat Transfer ◽  
Three Dimensional ◽  
Concave Surface ◽  
Air Jets ◽  
Hot Air

Heat Transfer for Round Air Jets Flowing Along a Concave Surface

2007 ◽  
Author(s):  
Ryuta Ito ◽  
Kenichiro Takeishi ◽  
Yutaka Oda ◽  
Naoki Yoshida
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Numerical Simulations ◽  
Large Scale ◽  
Concave Surface ◽  
Complex Flow ◽  
Free Jet ◽  
Recirculating Flow ◽  
Air Jets ◽  
Complex Flow Structure

Local Nusselt number distributions for a square array of round air jets impinging on a flat surface and a concave surface were measured in high resolution by naphthalene sublimation techniques. Corresponding numerical simulations using a realizable k-ε model were also conducted to investigate the heat transfer characteristics of the multiple jets and to clarify the complex flow structure. The experiments were conducted for Re = 5000, 10000, and 15000 at the non-dimensional nozzle to plate distance of 3.75. The Nusselt number for both flat and concave surfaces increased as Reynolds number increased from 5000 to 10000. Unexpectedly, experimental results showed the tendency of Nu to be saturated for Re = 15000, while showing a monotonic increase in numerical simulations. Most amount of wall jets from a central impinging jet formed large-scale recirculating flows, which surrounded free jet region of each jet, while some other wall jet were entrained by a small vortical structure near the target wall and merged into large-scale recirculating flow of the neighboring jets.

Computational Investigations of Flow and Heat Transfer on an Effused Concave Surface With a Single Row of Impinging Jets for Different Exit Configurations

2009 ◽  
Author(s):  
M. Ashok Kumar ◽  
B. V. S. S. S. Prasad
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Computational Study ◽  
Impinging Jets ◽  
Concave Surface ◽  
Local Enhancement ◽  
Stagnation Line ◽  
Single Row ◽  
Air Jets ◽  
Flow And Heat Transfer

A computational study is reported on flow and heat transfer from single row of circular air jets impinging on a concave surface with either one or two rows of effusion holes and without effusion holes. The effects of arrangement of jet orifices and effusion holes, spent air exit closure configurations, H/D ratio and jet Reynolds number are investigated. The pressure distribution is higher for the configuration with the air exit only through effusion holes. At higher Reynolds number, three peaks in local Nusselt number are identified and explained. Among the cases tested, the configuration with single row of inline effusion holes shows the least heat transfer and there is a significant local enhancement in heat transfer along the stagnation line for single row of staggered effusion holes. However, the effect of arrangement is negligible for two rows of effusion holes. Among the configuration tested the case of one edge open exit configuration with single row of staggered effusion holes (Case-C1s) shows higher heat transfer among others.

Drying of Rubber Sheet Using Impingement of Multiple Hot Air Jets

2013 ◽  
Vol 844 ◽  
pp. 502-506 ◽  
Author(s):  
Chayut Nuntadusit ◽  
Makatar Waehahyee
Keyword(s):  
Heat Transfer ◽  
Moisture Content ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Drying Rate ◽  
Rubber Sheet ◽  
Air Jets ◽  
Hot Air ◽  
Rubber Surface ◽  
Jet Velocity

In the process for producing ribbed smoked rubber sheet, the rubber sheet drying is the most time and energy consumption process. This research study the possibility in develop new drying system using array of hot air jets impinging directly on rubber sheet in order to reduce time for drying rubber in smoked room and increase productivity of rubber sheets. In the study, the array of jets from jet plate with drilled jet holes in staggered arrangement impinged on the both side of rubber sheet. The effects of jet velocity (Vj=10, 16, 23 m/s), jet temperature (Tj=50, 60, 70°C) and the distance from jet outlet to rubber surface (L=4D, 6D, 8D which D is diameter of jet hole) on drying rate were investigated by measuring weight of rubber sheet change with time. The heat transfer rate on impinged surface was also measured by attaching a heat flux sensor on impinged wall. The results showed that the convective heat transfer coefficient increased when the jet velocity was increased and when the distance from jet was decreased particularly in jet directly impinged region. It was found that the enhancement in heat transfer rate from jets cannot increase the rubber drying rate for all cases because the drying rate depend on rubber property. The process of rubber sheet drying can be divided in 2 periods; in the first drying period, the drying rate decreases with decreased moisture content. The drying rate depended on the initial moisture content and the condition of external effect such as jet velocity, jet temperature and distance from jet outlet to rubber surface. In second drying period, the moisture content is below 20% dry basis. In this period, the drying rate is almost constant near zero. It was also found that the drying for case of L=6D was higher than case of L=4D and 8D. The optimum condition for rubber sheet drying without defects on rubber property after drying was L=6D and Tj=70°C.

NUMERICAL STUDY OF A HOT-AIR-BASED AIRCRAFT WING ANTI-ICING SYSTEM USING THE BOX-BEHNKEN DoE APPROACH

2013 ◽  
Vol 37 (1) ◽  
pp. 111-128 ◽  
Author(s):  
Ridha Hannat ◽  
François Morency ◽  
Louis Decoster
Keyword(s):  
Heat Transfer ◽  
Thermal Conduction ◽  
Numerical Study ◽  
Internal Flow ◽  
Impact Angle ◽  
Quadratic Model ◽  
Box Behnken Design ◽  
Air Jets ◽  
Hot Air ◽  
Jet Impact

This article proposes the use of the Box-Behnken design of experiment (DoE) methodology to study an aircraft anti-icing system. The anti-icing system consisted of a piccolo tube with round apertures for producing air jets inside a wing. Mass flow, jet to wall distance, and jet impact angle were varied, starting from an initial design, in order to maximize heat transfer effectiveness. A conjugate heat transfer procedure from commercial CFD software was used to solve for cold air external flow, compressible internal flow, and thermal conduction in the airfoil skin. The DoE methodology was validated using a single impinging jet. A quadratic model of the heat transfer effectiveness of the anti-icing system was then built using the methodology and the maximal value was sought.

Sign in / Sign up

Export Citation Format

Share Document