ISSN Online: 2377-424X
ISBN Print: 978-1-56700-474-8
ISBN Online: 978-1-56700-473-1
International Heat Transfer Conference 16
THE STUDY OF HYDRODYNAMICS AND HEAT TRANSFER IN PEBBLE BEDS WITH VOLUMETRIC HEATING IN CASE OF AXIAL AND RADIAL FLOW
Abstract
The paper presents the results of an experimental and numerical study of hydrodynamics and heat transfer in a pebble bed with internal volumetric heat release. An experimental setup with two test sections was designed to investigate the hydrodynamics and heat transfer at the axial and radial flow of a single-phase coolant. The pebble bed was set from 2.0 mm diameter sphere made of AISI 420 steel. The internal heat release model in the pebble bed is provided by high-frequency induction heating, whereby the thermal power of the high-frequency installation is 20 kW. The experiments were carried out in the range of mass flow rates of 0.1 - 0.6 kg/s. To investigate the axial flow of the coolant at the work site, the pebbles were placed in a vertical cylindrical tube and held by perforated plates from the top and from the bottom. Data were obtained for pressure drop; the hydraulic resistance coefficients of the pebbles and the heat transfer coefficients were determined. For the first time, the hydraulic resistance coefficient of a perforated plate with an adjacent layer of pebbles was recorded. The working section for the study of transverse flow in the coolant simulates the fuel assembly of a nuclear reactor with microfuge. Pebbles are placed between the inner and outer perforated covers. Transverse coolant flow is achieved to minimize pressure losses. The inner cover is cone-shaped and is the dispensing manifold for the coolant. The conical shape of the cover provides a uniform flow rate of the cooling liquid along the length of the test section. The pressure drop and temperature distribution in the pebbles were recorded.
KEY WORDS:
heat transfer, hydrodynamics, porous media, pebble bed, internal heat release, convection