Author: Somchai Baotong
Publisher:
ISBN:
Category : Fourier transformations
Languages : en
Pages : 178
Book Description
The main objective of this research is to analyze and simulate the startup transient in two-phase natural circulation loop. Two rectangular loops have been designed and constructed to simulate a two-phase flow under two different configurations. Fast Fourier Transform (FFT) is used to analyze the oscillation of unstable temperature and differential pressure. A computer program, TEXAS, has been modified to simulate the two-phase flow in the rectangular natural circulation loop and compared with the experimental data. The same water temperature difference across the heater was measured both when the cooling system was turned on and turned off. The temperature oscillation was observed in both loops under unstable boiling condition. The temperature oscillation was due to two factors. The first factor was the presence of the horizontal tube. The second was the flow instabilities, known as geysering and flashing-induced density wave oscillation, which occurred when water flowed from small channel to large channel in the heated section. The frequency of the temperature oscillation at the condenser outlet increased when the heat flux increased. The results from the computer simulation agreed with the experimental results. However, the simulation had some limitation, and still required further modification.
Analysis and Simulation of Startup Transient in Two-phase Natural Circulation Loop
Author: Somchai Baotong
Publisher:
ISBN:
Category : Fourier transformations
Languages : en
Pages : 178
Book Description
The main objective of this research is to analyze and simulate the startup transient in two-phase natural circulation loop. Two rectangular loops have been designed and constructed to simulate a two-phase flow under two different configurations. Fast Fourier Transform (FFT) is used to analyze the oscillation of unstable temperature and differential pressure. A computer program, TEXAS, has been modified to simulate the two-phase flow in the rectangular natural circulation loop and compared with the experimental data. The same water temperature difference across the heater was measured both when the cooling system was turned on and turned off. The temperature oscillation was observed in both loops under unstable boiling condition. The temperature oscillation was due to two factors. The first factor was the presence of the horizontal tube. The second was the flow instabilities, known as geysering and flashing-induced density wave oscillation, which occurred when water flowed from small channel to large channel in the heated section. The frequency of the temperature oscillation at the condenser outlet increased when the heat flux increased. The results from the computer simulation agreed with the experimental results. However, the simulation had some limitation, and still required further modification.
Publisher:
ISBN:
Category : Fourier transformations
Languages : en
Pages : 178
Book Description
The main objective of this research is to analyze and simulate the startup transient in two-phase natural circulation loop. Two rectangular loops have been designed and constructed to simulate a two-phase flow under two different configurations. Fast Fourier Transform (FFT) is used to analyze the oscillation of unstable temperature and differential pressure. A computer program, TEXAS, has been modified to simulate the two-phase flow in the rectangular natural circulation loop and compared with the experimental data. The same water temperature difference across the heater was measured both when the cooling system was turned on and turned off. The temperature oscillation was observed in both loops under unstable boiling condition. The temperature oscillation was due to two factors. The first factor was the presence of the horizontal tube. The second was the flow instabilities, known as geysering and flashing-induced density wave oscillation, which occurred when water flowed from small channel to large channel in the heated section. The frequency of the temperature oscillation at the condenser outlet increased when the heat flux increased. The results from the computer simulation agreed with the experimental results. However, the simulation had some limitation, and still required further modification.
Transient Analysis of Two-phase Natural-circulation Systems
Author: R. P. Anderson
Publisher:
ISBN:
Category : Boiling water reactors
Languages : en
Pages : 46
Book Description
This publication presents a technique for solving the equations of a natural-circulation system. The solutions are compared with experimental results at various pressures with two geometries in boiling water systems.
Publisher:
ISBN:
Category : Boiling water reactors
Languages : en
Pages : 46
Book Description
This publication presents a technique for solving the equations of a natural-circulation system. The solutions are compared with experimental results at various pressures with two geometries in boiling water systems.
A Theoretical Study of the Transient Operation and Stability of Two-phase Natural Circulation Loops
Author: Kermit Garlid
Publisher:
ISBN:
Category : Fluid dynamics
Languages : en
Pages : 90
Book Description
Mathematical models of the time-dependent behavior of two-phase natural-circulation loops were used to predict the operation and to explain the unusual instability sometimes observed. The initial results obtained for a loop similar to the Univ. of Minnesota loop were used to formulate a more complex and accurate model, and the predicted transient behavior was in close agreement with the experimental results from the Minnesota loop. For a 300 psia, high-pressure loop, unstable oscillatory behavior was predicted under certain conditions and stable behavior under others. Closed unstable regions rather than limits were predicted, and the specifications of stability in terms of a single parameter were found to be impossible. The great difference in oscillatory frequencies observed at low and high pressures was found to be due largely to the system geometry. The criterion for the absence of oscillations was found to be similar to one of the criteria for stability of chemical reaction systems.
Publisher:
ISBN:
Category : Fluid dynamics
Languages : en
Pages : 90
Book Description
Mathematical models of the time-dependent behavior of two-phase natural-circulation loops were used to predict the operation and to explain the unusual instability sometimes observed. The initial results obtained for a loop similar to the Univ. of Minnesota loop were used to formulate a more complex and accurate model, and the predicted transient behavior was in close agreement with the experimental results from the Minnesota loop. For a 300 psia, high-pressure loop, unstable oscillatory behavior was predicted under certain conditions and stable behavior under others. Closed unstable regions rather than limits were predicted, and the specifications of stability in terms of a single parameter were found to be impossible. The great difference in oscillatory frequencies observed at low and high pressures was found to be due largely to the system geometry. The criterion for the absence of oscillations was found to be similar to one of the criteria for stability of chemical reaction systems.
The Transient Behavior of Single-phase Natural Circulation Water Loop Systems
A THEORETICAL STUDY OF THE TRANSIENT OPERATION AND STABILITY OF TWO-PHASE NATURAL CIRCULATION LOOPS.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Mathematical models of the time-dependent behavior of two-phase natural- circulation loops were used to predict the operation and to explain the unusual instability sometimes observed. The initial results obtained for a loop similar to the Univ. of Minnesota loop were used to formulate a more complex and accurate model, and the predicted transient behavior was in close agreement with the experimental results from the Minnesota loop. For a 300psia, high-pressure loop, unstable oscillatory behavior was predicted under certain conditions and stable behavior under others. Closed unstable regions rather than limits were predicted, and the specifications of stability in terms of a single parameter were found to be impossible. The great difference in oscillatory frequencies observed at low and high pressures was found to be due largely to the system geometry. The criterion for the absence of oscillations was found to be similar to one of the criteria for stability of chemical reaction systems. (D.L.C.).
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Mathematical models of the time-dependent behavior of two-phase natural- circulation loops were used to predict the operation and to explain the unusual instability sometimes observed. The initial results obtained for a loop similar to the Univ. of Minnesota loop were used to formulate a more complex and accurate model, and the predicted transient behavior was in close agreement with the experimental results from the Minnesota loop. For a 300psia, high-pressure loop, unstable oscillatory behavior was predicted under certain conditions and stable behavior under others. Closed unstable regions rather than limits were predicted, and the specifications of stability in terms of a single parameter were found to be impossible. The great difference in oscillatory frequencies observed at low and high pressures was found to be due largely to the system geometry. The criterion for the absence of oscillations was found to be similar to one of the criteria for stability of chemical reaction systems. (D.L.C.).
Experimental and Numerical Stability Investigations on Natural Circulation Boiling Water Reactors
Author: Christian Pablo Marcel
Publisher: IOS Press
ISBN: 1586038036
Category : Technology & Engineering
Languages : en
Pages : 160
Book Description
In the design of novel nuclear reactors active systems are replaced by passive ones in order to reduce the risk of failure. For that reason natural circulation is being considered as the primary cooling mechanism in next generation nuclear reactor designs such as the natural circulation boiling water reactor (BWR). In such a reactor, however, the flow is not a controlled parameter but is dependent on the power. As a result, the dynamical behavior significantly differs from that in conventional forced circulation BWRs. For that reason, predicting the stability characteristics of these reactors has to be carefully studied. In this work, a number of open issues are investigated regarding the stability of natural circulation BWRs (e.g. margins to instabilities at rated conditions, interaction between the thermal-hydraulics and the neutronics, and the occurrence of flashing induced instabilities) with a strong emphasis on experimental evidence.
Publisher: IOS Press
ISBN: 1586038036
Category : Technology & Engineering
Languages : en
Pages : 160
Book Description
In the design of novel nuclear reactors active systems are replaced by passive ones in order to reduce the risk of failure. For that reason natural circulation is being considered as the primary cooling mechanism in next generation nuclear reactor designs such as the natural circulation boiling water reactor (BWR). In such a reactor, however, the flow is not a controlled parameter but is dependent on the power. As a result, the dynamical behavior significantly differs from that in conventional forced circulation BWRs. For that reason, predicting the stability characteristics of these reactors has to be carefully studied. In this work, a number of open issues are investigated regarding the stability of natural circulation BWRs (e.g. margins to instabilities at rated conditions, interaction between the thermal-hydraulics and the neutronics, and the occurrence of flashing induced instabilities) with a strong emphasis on experimental evidence.
Nuclear Systems Volume II
Author: Neil E. Todreas
Publisher: CRC Press
ISBN: 1482239590
Category : Science
Languages : en
Pages : 659
Book Description
Discusses fundamental ideas for various modeling approaches for the macro- and micro-scale flow conditions in the reactor. Covers specific design considerations, such as natural convection and core reliability. Enables the reader to better understand the importance of safety considerations in thermal engineering and analysis of a modern nuclear plant. Features end-of-chapter problems. Includes a Solutions Manual for adopting instructors.
Publisher: CRC Press
ISBN: 1482239590
Category : Science
Languages : en
Pages : 659
Book Description
Discusses fundamental ideas for various modeling approaches for the macro- and micro-scale flow conditions in the reactor. Covers specific design considerations, such as natural convection and core reliability. Enables the reader to better understand the importance of safety considerations in thermal engineering and analysis of a modern nuclear plant. Features end-of-chapter problems. Includes a Solutions Manual for adopting instructors.