Solution of momento energy integral equations for natural convection in a vertical channel using symbolic computation

2019 ◽  
pp. 275-280
Author(s):  
M. Jayaram ◽  
S. Asok Kumar
Keyword(s):  
Natural Convection ◽  
Integral Equations ◽  
Symbolic Computation ◽  
Vertical Channel ◽  
Energy Integral

Turbulent Natural Convection in a Differentially Heated Vertical Channel

2008 ◽  
Author(s):  
Abolfazl Shiri ◽  
William K. George
Keyword(s):  
Boundary Layer ◽  
Natural Convection ◽  
Outer Region ◽  
Vertical Channel ◽  
Constant Heat Flux ◽  
Convection Boundary Layer ◽  
Turbulent Natural Convection ◽  
Scaling Parameters ◽  
The One ◽  
Momentum Integral

The turbulence natural convection boundary layer inside a infinite vertical channel with differentially heated walls is analyzed based on a similarity solution methodology. The differences between mean temperature and velocity profiles in a boundary layer along a vertical flat plate and in a channel flow, make it necessary to introduce new sets of scaling parameters. In the limit as H* → ∞, two distinctive parts are considered: an outer region which dominates the core of the flow and inner constant heat flux region close to the walls. The proper inner scaling velocity is showed to be determined by the outer parameters due to momentum integral. The theory is contrasted with the one suggested by George & Capp (1), the deficiencies of which are identified.

Experimental Study for Data Validation Regarding the Flow Movement in Natural Convection in an Asymmetrical Heated Vertical Channel

2014 ◽  
Vol 659 ◽  
pp. 313-318 ◽  
Author(s):  
Andrei Burlacu ◽  
Vasilică Ciocan ◽  
Marina Verdeș ◽  
Cătălin George Popovici ◽  
Marius Costel Balan ◽  
...  
Keyword(s):  
Experimental Study ◽  
Natural Convection ◽  
Particle Image ◽  
Single Channel ◽  
Size Variation ◽  
Vertical Channel ◽  
Heat Output ◽  
Piv Method ◽  
Physical Boundary ◽  
Zone Temperature

The present paper presents an experimental study, regarding the dynamics of movement in natural convection in an asymmetrically heated vertical channel. The channel was immersed in a tank filled with water at a temperature of 15 °C. The study focuses on one hand, on the radiated heat output from the heating plate, and on the other hand, on the thermo-physical boundary conditions from the inlet and the outlet of the channel. These aspects give great problems in natural convection if limited to a single channel as a field of study. The experimental study was conducted to validate numerical results, in similar conditions. The size variation of the recirculating zone, temperature and speed in the channel were analyzed through the PIV method (Particle Image Velocymetry) using the equipment provided by Dantec Dynamics and the analysis program "Dynamic Studio".

On Efficient Passive Cooling of Control Rod Drivers

2013 ◽  
Author(s):  
A. N. Gershuni ◽  
A. P. Nishchik ◽  
V. G. Razumovskiy ◽  
I. L. Pioro
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
High Performance ◽  
Cooling System ◽  
Vertical Channel ◽  
Passive Cooling ◽  
Primary Circuit ◽  
Two Phase ◽  
Primary Coolant ◽  
Control Rod

Experimental research of natural convection and the ways of its suppression in an annular vertical channel to simulate the conditions of cooling the control rod drivers of the reactor protection system (RPS) in its so-called wet design, where the drivers are cooled by primary circuit water supplied due to the system that includes branched pipelines, valves, pump, heat exchanger, etc., is reported. Reliability of the drivers depends upon their temperature ensured by operation of an active multi-element cooling system. Its replacement by an available passive cooling system is possible only under significant suppression of natural convection in control rod channel filled with primary coolant. The methods of suppression of natural convection proposed in the work have demonstrated the possibility both of minimization of axial heat transfer and of almost complete elimination of temperature non-uniformity and oscillation inside the channel under the conditions of free travel of moving element (control rod) in it. The obtained results widen the possibilities of substitution of the active systems of cooling the RPS drivers by reliable passive systems, such as high-performance heat-transfer systems of evaporation-condensation type with heat pipes or two-phase thermosyphons as heat-transferring elements.

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