# Steady state behavior of boiling channels: a comprehensive analysis using singularity theory

TL;DR: In this article, the steady state behavior of a boiling channel subject to a constant pressure drop was studied using singularity theory and the inlet velocity to the channel was chosen as the state variable.

Abstract: In this paper we present a comprehensive and a complete picture of the steady state behavior of a boiling channel subject to a constant pressure drop. To achieve this we have used singularity theory. The inlet velocity to the channel is chosen as the state variable. Its dependence on the imposed pressure drop chosen as the bifurcation parameter is depicted as bifurcation diagrams. The dependence of these diagrams on the values of the other parameters that occur in the model is discussed in detail. All possible bifurcation diagrams of the system are obtained and the parameter combinations that result in each kind of a diagram are identified. In this problem the Boundary Limit Set plays an important role. It generates a new critical surface in parameter space across which the bifurcation behavior changes.

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01 Jan 1985

TL;DR: Singularities and groups in bifurcation theory as mentioned in this paper have been used to solve the problem of finding a group of singularities in a set of problems with multiple solutions.

Abstract: This book has been written in a frankly partisian spirit-we believe that singularity theory offers an extremely useful approach to bifurcation prob- lems and we hope to convert the reader to this view In this preface we will discuss what we feel are the strengths of the singularity theory approach This discussion then Ieads naturally into a discussion of the contents of the book and the prerequisites for reading it Let us emphasize that our principal contribution in this area has been to apply pre-existing techniques from singularity theory, especially unfolding theory and classification theory, to bifurcation problems Many ofthe ideas in this part of singularity theory were originally proposed by Rene Thom; the subject was then developed rigorously by John Matherand extended by V I Arnold In applying this material to bifurcation problems, we were greatly encouraged by how weil the mathematical ideas of singularity theory meshed with the questions addressed by bifurcation theory Concerning our title, Singularities and Groups in Bifurcation Theory, it should be mentioned that the present text is the first volume in a two-volume sequence In this volume our emphasis is on singularity theory, with group theory playing a subordinate role In Volume II the emphasis will be more balanced Having made these remarks, Iet us set the context for the discussion of the strengths of the singularity theory approach to bifurcation As we use the term, bifurcation theory is the study of equations with multiple solutions

3,127 citations

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TL;DR: In this paper, a systematic, efficient scheme is presented for finding parameter values corresponding to a specific number of solutions. But this scheme is not suitable for large-scale systems, where many chemical reactions occur simultaneously with a large number of parameters.

Abstract: Mathematical models of lumped-parameter systems in which many chemical reactions occur simultaneously contain a large number of parameters, so that a p Theoretical guidance is needed to determine all the multiplicity features and the corresponding parameter regions. A systematic, efficient scheme is presented for finding parameter values corresponding to a specific number of solutions. A new scheme is developed for bifurcation diagrams, which describe the dependence of a state variable on a slowly changing operating variable. Some general predictions are made abou systems. Bounds on the values of the bifurcation or state variable may create bifurcation diagrams which cannot be found close to the highest order sin of solutions even when an isola variety does not exist. Several examples illustrate the application of the mathematical techniques.

154 citations

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TL;DR: Singularity theory with a distinguished parameter, as developed by Golubitsky and Schaeffer, is a very useful tool for predicting the influence of changes in a control or design variable on the steady-state of lumped-parameter systems as mentioned in this paper.

Abstract: Singularity theory with a distinguished parameter, as developed by Golubitsky and Schaeffer, is a very useful tool for predicting the influence of changes in a control or design variable on the steady-states of lumped-parameter systems. The theory is used to construct various bifurcation diagrams describing the influence of changes in the residence time on the temperature in a CSTR in which several reactions occur simultaneously. The number of different bifurcation diagrams increases very rapidly with increasing number of reactions. The predictions of this local theory provide important theoretical guidance in the global analysis of the multiplicity features.

132 citations

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TL;DR: In this article, the drift flux model is used to make the set of equations dimensionless to ensure the mutual independence of the dimensionless variables and parameters: the steady-state inlet velocity v, the inlet subcooling number N sub and the phase change number N pch.

Abstract: Linear and nonlinear mathematical stability analyses of parallel channel density wave oscillations are reported. The two phase flow is represented by the drift flux model. A constant characteristic velocity v 0 ∗ is used to make the set of equations dimensionless to ensure the mutual independence of the dimensionless variables and parameters: the steady-state inlet velocity v , the inlet subcooling number N sub and the phase change number N pch . The exact equation for the total channel pressure drop is perturbed about the steady-state for the linear and nonlinear analyses. The surface defining the marginal stability boundary (MSB) is determined in the three-dimensional equilibrium-solution/operating-parameter space v − N sub − N pch . The effects of the void distribution parameter C 0 and the drift velocity V g j on the MSB are examined. The MSB is shown to be sensitive to the value of C 0 and comparison with experimental data shows that the drift flux model with C 0 > 1 predicts the experimental MSB and the neighboring region of stable oscillations (limit cycles) considerably better than do the homogeneous equilibrium model ( C 0 = 1, V g j = 0 ) or a slip flow model. The nonlinear analysis shows that supercritical Hopf bifurcation occurs for the regions of parameter space studied; hence stable oscillatory solutions exist in the linearly unstable region in the vicinity of the MSB. That is, the stable fixed point v becomes unstable and bifurcates to a stable limit cycle as the MSB is crossed by varying N sub and/or N pch .

93 citations