Investigation of heat transfer and pressure drop in an annular channel with heat transfer intensifiers

2015 ◽  
Vol 62 (3) ◽  
pp. 177-182 ◽  
Author(s):  
E. A. Boltenko ◽  
A. N. Varava ◽  
A. V. Dedov ◽  
A. V. Zakharenkov ◽  
A. T. Komov ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Annular Channel

Scrutiny the Heat Transfer Effect in an Annulus by Mounting Axial Fins with Different Shapes: Without and with Taylor Number

2021 ◽  
Vol 409 ◽  
pp. 142-157
Author(s):  
Farouk Kebir ◽  
Youcef Attou
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Annular Channel ◽  
Reynolds Stress Model ◽  
Taylor Number ◽  
Maximum Heat ◽  
Maximum Heat Transfer ◽  
Rsm Model ◽  
Energy Equations ◽  
The Impact

This study aimed to investigate numerically the heat transfer improvement and pressure drop inside annular channel of a rotor-stator provided with fins mounted on the stator without and with Taylor number. The impact of mounting various types of fins (triangular, rectangular, trapezoidal shapes with small and large base) is studied by varying the fin width b from 0 to 14 mm. In the presence of axial air flow, numerical simulations are carried out by solving the governing continuity, momentum and energy equations of turbulent flow in cylindrical coordinates using the Finite Volume Method. The results obtained by Reynolds Stress Model RSM model have indicated that the heat transfer enhances as the surface area of the fins and the effective Reynolds number increase, while there is an increase in pressure drop. Furthermore, we have shown that the presence of Taylor number has a slight increase in Nusselt number and pressure drop compared to the case without Taylor number. Among the four geometries, it is found that the rectangular cavity is the best geometry which gives maximum heat transfer and minimum pressure loss.

On Experimental and Computational Investigation of Heat Transfer Deterioration and Hydraulic Resistance in Annular Channel and SCWR 3-Rod Bundle

2018 ◽  
Author(s):  
Vladislav V. Filonov ◽  
Yuliia S. Filonova ◽  
Victor G. Razumovskiy ◽  
Evgeniy N. Pis'mennyi
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Pressure Drop ◽  
Thermal State ◽  
Annular Channel ◽  
Operating Conditions ◽  
Mass Rate ◽  
Heat Transfer Deterioration ◽  
Annular Channels ◽  
Vertical Annuli

The experiments on upward flow of supercritical water in a vertical annuli and 3-rod tight bundle simulator made of 485-mm heated-length tubes of 5.2-mm OD and 4.5-mm ID with four helical ribs of 0.6-mm height, 1-mm width, and axial 400-mm pitch are presented. Heat transfer and pressure drop under various operating conditions (inlet pressure and temperature, flow mass rate and heat flux) were investigated. Longitudinal wall temperature profiles made it possible to determine the place and flow thermal state of heat transfer deterioration (HTD) onset. Analysis of the obtained data (about 200 regimes) proved their good enough agreement with the correlations previously derived by the authors both for the heat flux rate (q/G)b of HTD beginning and for pressure drop in round tubes and annular channels. These correlations were updated to correct the results of their prediction. Computational fluid dynamics and its counterpart computational heat transfer were used for modeling the above-mentioned thermohydraulic processes studied in the first part of the work by finding the most adequate flow turbulence model and optimized domain meshing. The accepted model was benchmarked by some data on heat transfer and pressure drop in tubes and annular channels cooled by SCW.

Experiments on Effect of Jet Impingement on Heat Transfer in Annular Channels With Parallel and Counter Flows

2002 ◽  
Author(s):  
S. Mhetras ◽  
S. C. Lau
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Annular Channel ◽  
Outer Tube ◽  
Counter Flow ◽  
Inner Surface ◽  
The Heat Transfer Coefficient ◽  
Flow Case

This experimental research examines, for turbulent parallel and counter flows of air through an annular channel, the effects of varying the geometries of the channel and the array of holes along the inner tube on the heat transfer distribution on the inner surface of the outer tube. Each hole array has 5 or 6 inline or staggered circular holes around the circumference of the inner tube at 10 axial stations along the inner tube. Heat transfer experiments are performed for three inner tube diameters, two hole diameters, and Reynolds numbers of 5,000, 12,250 and 30,000, to determine the distribution of the regional average Nusselt numbers along the outer tube, as a result of the jets impinging on its inner surface. Pressure measurements give the overall pressure drops, and the pressure distributions along the inner tube and the annular channel between the inner and outer tubes. The pressure data is needed to determine the mass flow rates of the impinging jets along the inner tube. The jets along the inner tube enhance the regional heat transfer on the inner surface of the outer tube by up to eight times when compared with the heat transfer for fully developed turbulent flow through an annular channel. Heat transfer enhancement is higher for a smaller inner tube and a lower Reynolds number. In the parallel flow case, the heat transfer coefficient on the outer wall of the annular channel is higher near the downstream end of the annular channel, while in the counter flow case, the heat transfer coefficient is higher near the upstream end of the annular channel. For both parallel and counter flows, the heat transfer coefficient is higher in a channel with a larger inner tube. With smaller holes along the inner tube, the heat transfer coefficient along the outer tube is higher and more uniform. Smaller holes, however, cause a higher overall pressure drop across the annular channel, resulting in a lower thermal performance. Increasing the total number of holes lowers the heat transfer, and causes a lower overall pressure drop. The hole mass flow rate increases along the main flow direction in the annular channel for parallel flow, and decreases for counter flow. The variation of the hole mass transfer is smaller for a larger inner tube diameter.

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