Structure of mixed convective longitudinal vortex air flow driven by a heated circular plate embedded in the bottom of a horizontal flat duct

Tuh, Jyh-Long; Lin, T.F.

doi:10.1016/s0017-9310(02)00425-8

Cited by 8 publications

(4 citation statements)

References 21 publications

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“…can also appear in the duct above the heated disk [3,20]. The longitudinal and transverse vortex flows are, respectively, characterized by the rolls with their rotation axes parallel and perpendicular to the main flow direction [22].…”

Section: Resultsmentioning

confidence: 99%

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Delayed onset of return flow by substrate inclination in model horizontal longitudinal MOCVD processes

Kuo¹,

Wang²,

Tuh³

et al. 2005

Journal of Crystal Growth

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Section: Resultsmentioning

confidence: 99%

“…The experimental system established in the previous study [3,20] is also used here with a slight modification of the test section. Fig.…”

Section: Experimental Apparatus and Proceduresmentioning

confidence: 99%

Delayed onset of return flow by substrate inclination in model horizontal longitudinal MOCVD processes

Kuo¹,

Wang²,

Tuh³

et al. 2005

Journal of Crystal Growth

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“…It is of interest to note that at Re ¼ 30:4 some longitudinal recirculations in the form of parallel vortex rolls with all their axes in the forced flow direction are induced in the exit half of the duct, as evident from the steady top and side view flow photos shown in Fig. 3 for Re ¼ 30:4 and Ra ¼ 11; 754: The characteristics of the longitudinal vortex rolls and their generation have been examined in a recent study of Tuh and Lin [17]. These top and side view flow photos manifest that the return flow does not exist in the entire duct.…”

Section: Return Flow At Steady or Statistically Stable Statementioning

confidence: 92%

Visualization of return flow structure in mixed convection of gas over a heated circular plate in a horizontal flat duct

Tuh

Lin

2003

Journal of Crystal Growth

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Experimental flow visualization is conducted here to investigate the buoyancy-induced return flow structure in mixed convection of gas over a heated circular plate mounted on the bottom of a horizontal flat duct, simulating that in a horizontal longitudinal flow reactor. In particular, how the return flow induced in the upstream portion of the duct is related to the vortex flow in the downstream is delineated. The results show that at a low buoyancy-to-inertia ratio only steady longitudinal vortex rolls (L-rolls) are induced in the exit half of the duct and no return flow appears in the duct. At an intermediate buoyancy-to-inertia ratio a small flow recirculation exists around the duct inlet near the top wall and the L-rolls become unsteady. When the buoyancy-to-inertia ratio is high and the Reynolds number is small with Reo10; the upstream return flow is strong and occupies a large region. There is another return flow zone around the exit end of the duct. Over the heated circular plate the flow is dominated by the moving transverse rolls (T-rolls). Moreover, the return flow around the duct inlet at steady or statistically stable state is in the form of a semicircular roll around the upstream edge of the circular plate. Flow visualization also reveals that the splitting of the downstream tip of the return flow zone and the rising of the buoyancy-driven spanwisely extended thermal under the tip generate a pair of counter-rotating transverse rolls in the entry portion of the duct. In addition, the criterion for the onset of the return flow near the duct inlet, the size and the center position of the return flow, based on the present experimental data, are correlated empirically.

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“…An experiment was carried out by [7] to investigate the structure of the longitudinal vortex rolls in mixed convective air flow through a horizontal flat duct with a circular heated plate embedded in the duct bottom. The observed rolls in the throughflow have not the same size; in fact, they are not completely spanwisely symmetric.…”

Section: Introductionmentioning

confidence: 99%

An experimental analysis in horizontal convection with IR thermography

Ceglia¹,

Discetti²

2012

Proceedings of the 2012 International Conference on Quantitative InfraRed Thermography

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The aim of this work is to investigate by means of infrared thermography the features of the boundary layer developing on the bottom base of a water-filled volume where a differential heating input is provided. The circulation induced by piecewise thermal conditions on a horizontal boundary is commonly referred as horizontal convection. In the present study, a uniform temperature is imposed on one half of the bottom base of a Plexiglass® box filled with degassed water, while on the other half a uniform heat flux input is provided; on the other box boundaries, the condition of adiabatic wall is reproduced. The range of tested RaL numbers (referred to the heat flux input and box depth) is 5.54x10 9 ÷7.63x10 10 . The transition of the boundary layer and the development of the time evolution of the coherent structures motion are observed on the half base where the uniform heat flux input is provided. At the same location, the onset of longitudinal streamwise rolls and, subsequently, the rise of a strong vertical plume are followed for all the tested operating conditions.

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Structure of mixed convective longitudinal vortex air flow driven by a heated circular plate embedded in the bottom of a horizontal flat duct

Cited by 8 publications

References 21 publications

Delayed onset of return flow by substrate inclination in model horizontal longitudinal MOCVD processes

Delayed onset of return flow by substrate inclination in model horizontal longitudinal MOCVD processes

Visualization of return flow structure in mixed convection of gas over a heated circular plate in a horizontal flat duct

An experimental analysis in horizontal convection with IR thermography

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