A Model for Thermal-Hydraulic Characteristics of Offset Strip Fin Arrays for Large Prandtl Number Liquids

The Fluoride-salt-cooled High temperature Reactors (FHRs) are an advanced concept using a novel combination of high-temperature coated-particle fuel, low-pressure fluoride-salt coolant and air-Brayton power conversion system. Prismatic fuel or pebble fuel are adopted for the conceptual core designs of FHRs like TMSR-SF, MK1 PB-FHR and SM-AHTR. The high-Prandtl-number FLiBe is mainly adopted as the primary coolant, which specifies in high melting and boiling point and high volumetric capacity. The experimental results obtained from the air, water or inert gas prove reliable for the Prandtl number vary from 0.7 to 7. Little experimental research has been conducted to prove applicability of the above results to the high-Prandtl fluid, fluoride salts in the packed pebble bed. In this paper, a pebble bed experimental facility has been designed and constructed for the FHRs to explore the thermal-hydraulic characteristics of fluoride salts in the reactor pebble bed core. Dowtherm A is adopted as a simulant fluid for the fluoride salts. The cylindrical test section is packed with steel pebbles. The electromagnetic induction heating system is used to provide internal heat source for the pebble beds. The forced flow and convective heat transfer of high-Prandtl-number fluid in the pebble bed with internal heat generation are investigated in the experiment. The fluid inlet temperature and mass flow rate are studied on the thermal-hydraulic characteristics.

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Modeling the f and j Characteristics for Transverse Flow Through an Offset Strip Fin at Low Reynolds Number

10.1115/imece1999-0973 ◽

1999 ◽

Author(s):

Y. S. Muzychka ◽

M. M. Yovanovich

Keyword(s):

Heat Transfer ◽

Fundamental Solutions ◽

Transverse Flow ◽

Low Flow ◽

Hydraulic Characteristics ◽

Model Predictions ◽

Flow Through ◽

Factor Data ◽

Analytic Models ◽

Offset Strip Fin

Abstract Analytic models for predicting the thermal-hydraulic characteristics for transverse flow through an offset strip fin array are developed. These models are developed by combining the creeping or low flow asymptotic behaviour with laminar and turbulent boundary layer wake models. Expressions for each of these characteristic regions are developed using fundamental solutions of fluid dynamics and heat transfer. The proposed models are compared with new experimental data for ten offset strip fin configurations. Model predictions are within ± 20 percent for 92 percent of friction factor data and 71 percent for Colburn j factor data.

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Modeling the f and j Characteristics of the Offset Strip Fin Array

10.1115/imece1999-0974 ◽

1999 ◽

Author(s):

Y. S. Muzychka ◽

M. M. Yovanovich

Keyword(s):

Experimental Data ◽

Asymptotic Behaviour ◽

Friction Factor ◽

Turbulent Wake ◽

Hydraulic Characteristics ◽

Model Predictions ◽

New Models ◽

Factor Data ◽

Offset Strip Fin

Abstract New models for predicting the thermal-hydraulic characteristics of offset strip fin arrays are developed. These models are developed by combining the asymptotic behaviour for the laminar and turbulent wake regions. Models in these two regions are developed by considering the offset strip fin as an array of short ducts or channels. The proposed models are compared with published experimental data for nineteen configurations of the rectangular offset strip fin. Model predictions are within ± 20 percent for 96 percent of friction factor data and 82 percent for Colburn j factor data. Extension of the new models for offset strip fins having non-rectangular subchannels is also discussed.

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MODELING THE HYDRAULIC CHARACTERISTICS OF DRAIN VALVE AND BURST FITTING OF AN AIRCRAFT ACCIDENT-RESISTANT FUEL SYSTEM

Computational nanotechnology ◽

10.33693/2313-223x-2020-7-3-37-44 ◽

2020 ◽

Vol 7 (3) ◽

pp. 37-44

Author(s):

KONSTANTIN NAPREENKO ◽

◽

ROMAN SAVELEV ◽

ALEKSEY TROFIMOV ◽

ANNA LAMTYUGINA ◽

...

Keyword(s):

Mathematical Modeling ◽

Hydraulic Resistance ◽

Hydraulic Calculation ◽

Fuel System ◽

Hydraulic Characteristics ◽

System A ◽

Ansys Cfx ◽

Calculation Results ◽

Scale Experiment ◽

Aircraft Accident

The article discusses methods for determining the hydraulic resistance of units of an accident-resistant fuel system. A detailed description of the need to create such fuel systems for modern helicopters is given. The development of such systems today is impossible without the use of the method of mathematical modeling, which allows to qualitatively solve problems arising in the design process. To obtain accurate research results, it is necessary to have a complete description of all elements and assemblies of the system. Methods for determining the hydraulic characteristics of AFS elements using the drag coefficient, reference literature and CFD codes are considered. As the investigated AFS units, a drain valve and burst fitting were studied in the article. A hydraulic calculation of these AFS elements ware performed, the simulation results are presented in the ANSYS CFX software package. Also as the calculation results of bursting fitting, the pressure distribution fields of full and static pressure, velocity and streamlines are also shown. An experimental setup for validating the results obtained using the mathematical modeling method is considered, as well as a methodology for conducting a full-scale experiment to determine the hydraulic resistance of the unit. Materials have been prepared for inclusion in a one-dimensional mathematical model of an accident-resistant fuel system.

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