Modeling of flashing-induced flow instabilities for a natural circulation driven novel modular reactor

The paper describes the results of recent experiments carried out in the Cavitating Pump Rotordynamic Test Facility for the dynamic characterization of cavitation-induced flow instabilities as simultaneously observed in the stationary and rotating frames of a high-head, three-bladed axial inducer with tapered hub and variable pitch. The flow instabilities occurring in the eye and inside the blading of the inducer have been detected, identified, and monitored by means of the spectral analysis of the pressure measurements simultaneously performed in the stationary and rotating frames by multiple transducers mounted on the casing near the inducer eye and on the inducer hub along the blade channels. An interaction between the unstable flows in the pump inlet and in the blade channels during cavitating regime has been detected. The interaction is between a low frequency axial phenomenon, which cyclically fills and empties each blade channel with cavitation, and a rotating phenomenon detected in the inducer eye.

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Computational Analysis of Static Flow Instabilities in Supercritical Natural Circulation Loop

Lecture Notes in Mechanical Engineering - Proceedings of International Conference on Thermofluids ◽

10.1007/978-981-15-7831-1_35 ◽

2020 ◽

pp. 387-395

Author(s):

Santosh Kumar Rai ◽

Pardeep Kumar ◽

Vinay Panwar

Keyword(s):

Computational Analysis ◽

Natural Circulation ◽

Flow Instabilities ◽

Circulation Loop ◽

Natural Circulation Loop ◽

Static Flow

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Description of Typical Flow Instabilities in the Natural Circulation System

10th International Conference on Nuclear Engineering, Volume 3 ◽

10.1115/icone10-22037 ◽

2002 ◽

Author(s):

Shengyao Jiang ◽

Xingtuan Yang ◽

Youjie Zhang

Keyword(s):

Natural Circulation ◽

Great Influence ◽

Operating Conditions ◽

Boiling Water ◽

Flow Instabilities ◽

Circulation System ◽

Boiling Water Reactor ◽

Primary Loop ◽

Water Reactor ◽

Test Loop

The experiments were performed on the test loop HRTL-5, which simulates geometry and system design of the 5-MW Nuclear Heating Reactor developed by the Institute of Nuclear Energy Technology, Tsinghua University. Because of the difference of the geometry design and operating conditions between the heating reactor and the boiling water reactor, the flow behavior presents great differences too, some of which haven’t been deeply studied so far. Results show that in heating reactor, sub-cooled boiling, condensation and flashing play an important role on the flow instabilities of the natural circulation system. Correspondingly, geysering instability, flashing instability, and flow excursion are the very typical instabilities occurring in the primary loop of HRTL-5, which are different from those in boiling water reactor conditions. The compressibility of the steam space on the top of the primary loop has also great influence on the instability of the natural circulation system.

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Study of flow instabilities in double-channel natural circulation boiling systems

Nuclear Engineering and Design ◽

10.1016/j.nucengdes.2008.01.007 ◽

2008 ◽

Vol 238 (7) ◽

pp. 1750-1761 ◽

Cited By ~ 26

Author(s):

Gonella V. Durga Prasad ◽

Manmohan Pandey ◽

Santosh K. Pradhan ◽

Satish K. Gupta

Keyword(s):

Natural Circulation ◽

Flow Instabilities ◽

Double Channel

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Performance Comparison of Flat Plate Collectors Fitted With Non Circular Risers With Integral Fins

Energy Conversion and Resources ◽

10.1115/imece2005-82933 ◽

2005 ◽

Cited By ~ 1

Author(s):

V. R. Bhore ◽

S. B. Thombre

Keyword(s):

Flat Plate ◽

Unit Area ◽

Natural Circulation ◽

Performance Comparison ◽

Test Results ◽

Absorber Plate ◽

Circulation Mode ◽

Induced Flow ◽

Flat Plate Collector ◽

Buoyancy Induced Flow

The present study deals with comparison of experimentally determined performance characteristics of solar flat plate collectors fitted with novel designs of absorber plate involving non-circular risers with integral fins and operating under natural circulation mode. The main flow passages considered were square, triangular and semicircular in cross section. One standard solar flat plate collector with circular risers was also tested simultaneously for direct comparison. The test results indicate that the absorber fitted with the triangular sectioned risers yields the best performance in terms of the efficiency (63%), and the buoyancy induced flow per unit area (76 kg/hr-m2) from amongst the collectors investigated. It is followed by the absorbers fitted with the semicircular and square sectioned risers respectively. The standard solar flat plate collector is found to yield the lowest values i.e. 46 % and 40 kg/hr-m2 respectively.

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