3. Operands#
3.1. Keyword FAISCEAU_TRANS#
♦/FAISCEAU_TRANS
Keyword factor for characterizing a « bundle of tubes under transverse flow » type configuration. If the study is based on the definition of several areas of excitement, it requires as many occurrences of the keyword factor FAISCEAU_TRANS as there are zones.
◊ COUPLAGE = 'OUI' or 'NON'
A text-type indicator that specifies whether or not fluid-elastic forces are taken into account. This operand must appear in at least one occurrence of the keyword factor FAISCEAU_TRANS, and may be omitted in the others.
◊ CARA_ELEM = cara
[cara_elem] concept allowing to provide all the data relating to the geometry of the elements of the structure: useful for estimating the hydraulic diameter. This operand must appear in at least one occurrence of the keyword factor FAISCEAU_TRANS, and may be omitted in the others.
♦ PROF_VITE_FLUI = profv
Concept of type [function] to provide the dimensionless transverse speed profile along the tube. The function parameter is the curvilinear abscissa. This operand should appear in all occurrences of the keyword factor FAISCEAU_TRANS.
◊ PROF_RHO_F_INT = profroy
Type concept [function] for providing the density profile of the fluid inside the tube, along the tube. The function parameter is the curvilinear abscissa. This operand must appear in at least one occurrence of the keyword factor FAISCEAU_TRANS, and may be omitted in the others.
◊ PROF_RHO_F_EXT = prophoe
Type concept [function] for providing the density profile of the fluid external to the tube, along the tube. The function parameter is the curvilinear abscissa. This operand must appear in at least one occurrence of the keyword factor FAISCEAU_TRANS, and may be omitted in the others.
◊ NOM_CMP = 'DX' or 'DY' or 'DZ'
A text-type indicator [TXM] that specifies the direction in which fluid-elastic and/or turbulent forces act. This operand must appear in at least one occurrence of the keyword factor FAISCEAU_TRANS, and may be omitted in the others.
◊ COEF_MASS_AJOU = cm
Value of the added mass coefficient cm. This operand, if used, may only be defined in one occurrence of the keyword factor FAISCEAU_TRANS, and may be omitted in the others.
List of two real numbers defining the range of Connors constants for the method of the same name (see R4.07.04).
Tube density for the Connors method
Number of discretization points within the interval defined by the CSTE_CONNORS keyword presented above.
◊/◊ TYPE_PAS = 'CARRE_LIGN' or 'TRIA_LIGN'
Text type indicator [TXM] for specifying the type of beam step, defined by the arrangement of the tubes in relation to each other and by the direction of the flow in relation to the beam. This operand may only appear in one occurrence of the keyword factor FAISCEAU_TRANS, and may be omitted in the others.
'CARRE_LIGN' = step square line.
'TRIA_LIGN' = not triangular line.
♦ TYPE_RESEAU = tr
An integer indicator strictly less than 1000 and positive defining the experimental configuration for which the coupling coefficients used for the study were obtained [bib1]. This operand should appear in all occurrences of the keyword factor FAISCEAU_TRANS.
Note:
« tr » must appear in two files « cd.70 » and « ck.71 » which make it possible to describe the evolution of the damping and the stiffness added by the flow as a function of the reduced speed \({V}_{r}\) , the latter being calculated from the inter-tube speed.
The files « cd.70 » and « ck.71 » are read by the logical units 70 and 71. They both have the following structure:
**Line 1 of the file: number of correlations present in the whole file (integer)*
**then, for each of these correlations, a block composed of**
**Line 1 of the block: type of network step associated with the correlation (1 if* TYPE_PAS = « CARRE_LIGN », 2 if TYPE_PAS = « TRIA_LIGN »)
**Line 2 of the block:tr (integer entered at the operand* « TYPE_RESEAU »)
**Line 3 of the block:nbranges (number of contiguous ranges of reduced speed over which the added damping and stiffness have been interpolated by the user in polynomial form)*
**Line 4 of the block: nbreal ranges, followed by two real numbers A and B; the real prime nbranges correspond to the reduced speed values - ordered in ascending order - of the lower limits of the contiguous nbranges; the two reals* \(A\) and \(B\) are respectively the smallest and the largest values of reduced speed for which the damping and the added stiffness were determined experimentally on a test bench in thermohydraulic similarity; So they delimit the beach of reduced speeds within which the correlation can be interpolated from the values identified on the test bench. In general, we therefore choose the first of the real nbranges equal to \(A\) and the last of the nbreal ranges equal to \(B\) .
**Nbranges following lines: each line corresponds to the polynomial interpolation of the damping correlation or the stiffness added in the range considered, the first reduced speed range extending between the first and the second of the first and the second of the real nbranges. On each line, 11 coefficients must be entered. These coefficients are* \({({\alpha }_{i})}_{1\le i\le 11}\) defining the polynomial used for interpolation in the range considered. So, for example, \({C}_{d}\) designating the damping added by the flow. The expression that will be taken into account based on the reduced speed is the following \({V}_{r}\) (the expression for the added stiffness is analogous) :
\({C}_{d}({V}_{r})=\sum _{i=1}^{11}{\alpha }_{i}{V}_{r}^{(i-4)}\)
Next line: a line to delimit the blocks associated with each correlation, generally of the form: « » *
**end of the block**
If there are other correlations, Line 1 of the block corresponding to the next correlation.
Based on a number of tests, EDF developed and validated a set of fluid-elastic correlations to simulate the damping and stiffness added to a structure by a flow. The provision of these correlations in the form of two files of a format in accordance with the one specified above will be studied on a case-by-case basis according to the request.
◊ UNITE_CA = iu1
Number of the logical unit in which the « cd.70 » file of depreciations added by the flow is written.
Number of the logical unit in which the file « cd.71 » of the stiffness added by the flow is written.
◊ PAS = step
Value of the reduced step of the bundle: ratio between, on the one hand, the inter-axis between 2 neighboring tubes, and on the other hand, the external diameter of the tubes. This operand may only appear in one occurrence of the keyword factor FAISCEAU_TRANS, and may be omitted in the others.
3.2. Keyword GRAPPE#
♦/GRAPPE
Keyword factor used to characterize a « control cluster » configuration.
♦ COUPLAGE = 'OUI' or 'NON'
Text type indicator [TXM] specifying the consideration of fluid-elastic forces.
Fluid-elastic coupling, if taken into account, involves the dimensionless coefficients of fluid-elastic forces identified on model GRAPPE2, which are used to represent a resulting force and moment [bib2].
If COUPLAGE = “OUI”, the following operands must be filled in, with the exception of COEF_MASS_AJOU which is optional.
◊/♦ GRAPPE_2 = 'ASC_CEN' or 'ASC_EXC' or '' or 'DES_CEN' or 'DES_EXC'
Four possible choices corresponding to the various experimental configurations for which the fluid-elastic force coefficients have been identified:
flow ASCendant CENtrée control rod;
flow ASCendant EXCentrée control rod;
flow DEScendant CENtrée control rod;
flow DEScendant EXCentrée control rod.
♦ GROUP_NO = big
Identifier of the node where the resulting force and moment representing the action of fluid-elastic forces are applied.
♦ CARA_ELEM = Cara
[cara_elem] type concept providing all the data relating to the geometry of the elements of the structure: useful for estimating the diameter of the control rod. Among other things, this concept provides information about the orientations of the elements.
♦ MODELE = model
Type concept [model] providing information about the types of elements in the structure.
◊ COEF_MASS_AJOU = cm1
Value of the coefficient of added mass due to the local confinement of the control rod at the level of the housing plate. If the modal water characteristics at rest of the structure have been calculated with the equivalent density.
\({\rho }_{\mathrm{eq}}=\alpha \frac{\pi {D}^{2}}{\mathrm{4S}}{\rho }_{\mathrm{eau}}+{\rho }_{\mathrm{poutre}}\)
The coefficient cm1 of added mass due to local confinement at the level of the housing plate is given by the relationship:
\(\text{cm1}=\frac{\pi (-\alpha )}{2}\)
where \(D\) designates the outside diameter of the rod; \(S\) is the area of the straight section of the tube and \(H\) represents the thickness of the fluid film at the confinement level.
Note:
When the user does not fill in the operand COEF_MASS_AJOU, cm1**is estimated automatically using this expression with:math:`alpha =1`* . *
♦ RHO_FLUI = rho_f
Value of the density of the fluid surrounding the structure.
3.3. Keyword FAISCEAU_AXIAL#
♦/FAISCEAU_AXIAL
Keyword factor for characterizing a configuration such as a « bundle of tubes under axial flow » [bib2].
Note:
In the case where the study is carried out using a representation of the full beam, only one occurrence is allowed for this keyword factor.
If the study is based on a simplified representation, as many occurrences as there are tubes in the simplified bundle are required. Each tube in the simplified bundle defines an equivalence class for the tubes in the real bundle. The characteristics of the tubes in the real bundle for the same equivalence class (common radius, positions) are the subject of an occurrence of the keyword factor.
To be able to use a simplified representation of the beam, the modal base calculated in air must be equivalent to the complete modal base in air of the real beam; each tube in the simplified beam must therefore be a tube equivalent to each class of real tubes. For example, for a class of \(N\) real tubes, Young modulus \(E\) , and density \(\rho\) , a possible equivalent tube is characterized by a Young modulus \(\mathit{NE}\) and a density \(N\rho\) .
♦/GROUP_MA = l_grma
In the case where the study focuses on the complete bundle: list of the groups of cells corresponding to the tubes of the bundle (concepts such as [group_ma]).
In the case where the study is based on a simplified representation: the use of this operand is mandatory and excludes the use of TRI_GROUP_MA. A concept of the [group_ma] type corresponding to one of the equivalent tubes of the simplified bundle is expected.
/TRI_GROUP_MA = 'root*' or '*root*' or '*root'
Text argument [TXM] defining the root of the names of the mesh groups corresponding to the tubes in the bundle. The use of this operand is only lawful in the case where the study is carried out using a representation of the complete beam. The root can be a prefix, an intermediate string, or a suffix.
♦ VECT_X = l_comp
List of three real numbers giving the components of the direction vector of the beam in the global coordinate system. Since the beam must be oriented along one of the axes of the global coordinate system, only three sets of components are acceptable: \((1.\mathrm{,0}\mathrm{.}\mathrm{,0}\mathrm{.})\), \((0.\mathrm{,1}\mathrm{.}\mathrm{,0}\mathrm{.})\) or \((0.\mathrm{,0}\mathrm{.}\mathrm{,1}\mathrm{.})\). This operand is mandatory if the study focuses on the complete cluster, and must appear at least in one of the occurrences of the keyword factor if the study is based on a simplified representation.
♦ PROF_RHO_FLUI = profrho
Type concept [function] defining the density profile of the fluid surrounding the tubes. The function parameter is the space coordinate corresponding to the axis of the global coordinate system directing the tube bundle. This operand is mandatory if the study focuses on the complete cluster, and must appear at least in one of the occurrences of the keyword factor if the study is based on a simplified representation.
♦ PROF_VISC_CINE = profvisc
Type concept [function] defining the kinematic viscosity profile of the fluid surrounding the tubes. The function parameter is the space coordinate corresponding to the axis of the global coordinate system directing the tube bundle. This operand is mandatory if the study focuses on the complete cluster, and must appear at least in one of the occurrences of the keyword factor if the study is based on a simplified representation.
♦/CARA_ELEM = cara
[cara_elem] concept providing all the data relating to the geometry of the elements of the structure: radius of each of the tubes. This concept is only to be provided in the case where the study focuses on the complete beam.
/♦ RAYON_TUBE = radius
Radius of the tubes of the real bundle for the same equivalence class. This operand is only used in the case where the study is based on a simplified representation.
♦ COOR_TUBE = l_coor
List of the coordinates of the centers of the tubes in the real bundle belonging to the same equivalence class. This operand is only used in the case where the study is based on a simplified representation.
◊ PESANTEUR = l_g
List of four real numbers defining the magnitude and orientation of the gravity vector \(g\) in the global coordinate system. Data \((g,{a}_{p},{b}_{p},{c}_{p})\) must be provided in order such as:
\(g=g\frac{{a}_{p}X+{b}_{p}Y+{c}_{p}Z}{\sqrt{{a}_{p}^{2}+{b}_{p}^{2}+{c}_{p}^{2}}}\)
The default values are: \(g\mathrm{=}9.81\); \({a}_{p}\mathrm{=}0.\);; \({b}_{p}\mathrm{=}0.\); \({c}_{p}\mathrm{=}–1.\)
♦ RUGO_TUBE = rug
Value of the absolute roughness of the walls of the tubes, used to estimate the coefficient of axial friction. This operand is mandatory if the study focuses on the complete cluster, and must appear at least in one of the occurrences of the keyword factor if the study is based on a simplified representation. A characteristic value for smooth steel is 10—5 meters.
♦ CARA_PAROI = l_cara
List of text arguments [TXM] giving the names of the geometric characteristics of the enclosure surrounding the beam. The legitimate arguments are as follows:
“YC”, “ZC” and “R” in the case of a circular enclosure: “YC”, “ZC” coordinates of the center in any plane \(x\mathrm{=}{x}_{0}\) along the axes of the global coordinate system perpendicular to the beam and ordered such that (X, Y, Z) is direct such that (X, Y, Z) is direct if X is the axis of the global coordinate system oriented along the beam. “R” ray.
“YC”, “ZC”, “HY” and “HZ” in the case of a rectangular enclosure: “YC”, “ZC” coordinates of the center in any \(x\mathrm{=}{x}_{0}\) plane. “HY”, “HZ” dimensions of the sides of the enclosure parallel to the Y and Z directions respectively.
♦ VALE_PAROI = l_vale
List of reals giving the values of the geometric characteristics, in correspondence with the list of names received for CARA_PAROI.
◊ ANGL_VRIL = alpha
Angle of rotation (in degrees) around the direction axis of the beam for a rectangular enclosure. This operand is mandatory if you define a rectangular enclosure by CARA_PAROI and VALE_PAROI. It is forbidden in the case of a circular enclosure.
Note:
The operands CARA_PAROI and VALE_PAROI are mandatory when the study focuses on the full beam. When the study is based on a simplified representation, these operands must appear together in at least one of the occurrences of the keyword factor FAISCEAU_AXIAL. The operand ANGL_VRIL must also be present in the same occurrence if one defines a rectangular enclosure.
Example:
Global coordinate system \((x,y,z)\) \(y\) beam axis
Note:
In the case where the study is carried out taking into account the grids of the tube bundle, the user must fill in each of the following eight operands. Remember that the geometry of a grid is a prismatic network with a square base.
*There may be several types of grates; for example, end grates and mixing grids in fuel assemblies. Grids of the same type are characterised**by identical dimensions and coefficients. *
List of reals giving the lengths of each type of grid in the tube bundle. The length of a grid is its dimension in the direction of the beam.
List of real numbers giving the widths of each type of grid. The width of a grid is its dimension in the plane perpendicular to the axis of the beam (i.e. the length of the side of the network).
List of real numbers giving the thicknesses of each type of grid. What is called grid thickness is the thickness of the network constituting the grid in a section perpendicular to the axis of the beam.
Grid example:
Global coordinate system \((x,y,z)\) \(y\) beam axis
List of reals giving the roughness height of each type of grid. These roughnesses are used to estimate the axial friction coefficient of each grid.
List of reals giving the drag coefficient for each type of grid. These drag coefficients make it possible to calculate the drag forces exerted by each grid on the axial flow of the fluid.
List of reals giving the slope (with zero incidence) of the lift coefficient of each type of grid, which is assumed to be slightly inclined. These coefficients make it possible to calculate the lift forces exerted by each grid on the flow of the fluid.
List of coordinates \(y\) (along the axis of the beam) of the discretization points of each of the grids. These coordinates correspond to the midpoints (halfway through the length) of the grids.
List of integers defining the type of each grid.
3.4. Keyword COQUE_COAX#
♦/COQUE_COAX
Keyword factor for characterizing a configuration consisting of two coaxial cylindrical shells separated by an annular gap in which a fluid flows [bib2].
◊ MASS_AJOU = 'OUI' or 'NON'
A text-type indicator [TXM] by which the user specifies whether or not to take into account added mass effects, in addition to added damping and stiffness effects.
♦ GROUP_MA_INT = gr_ma_i
Identifier of the group of elements (concept of type [group_ma]) corresponding to the inner shell.
♦ GROUP_MA_EXT = gr_ma_e
Identifier of the group of elements (concept of type [group_ma]) corresponding to the outer shell.
♦ VECT_X = l_comp
List of three real numbers giving the components of the direction vector of the axis of revolution of the two shells in the global coordinate system. Since the axis of revolution of the shells must be one of the axes of the global coordinate system, only three sets of components are acceptable: \((1.\mathrm{,0}\mathrm{.}\mathrm{,0}\mathrm{.})\), \((0.\mathrm{,1}\mathrm{.}\mathrm{,0}\mathrm{.})\) or \((0.\mathrm{,0}\mathrm{.}\mathrm{,1}\mathrm{.})\).
♦ CARA_ELEM = Cara
[cara_elem] type concept providing all the geometric characteristics of the elements.
♦ MATER_INT = mater_i
A concept of the [subdue] type providing all the physical quantities characteristic of the material constituting the internal structure.
♦ MATER_EXT = mater_e
A concept of the [subdue] type providing all the physical quantities characteristic of the material constituting the external structure.
♦ RHO_FLUI = rho_f
Density of the fluid.
♦ VISC_CINE = visco
Kinematic viscosity of the fluid.
♦ RUGOSITE = rug
Absolute shell wall roughness. A characteristic value for smooth steel is 10—5 meters.
♦ PDC_MOY_1 = code
Stationary (average) part of the coefficient of singular input pressure losses.
♦ PDC_DYN_1 = cdep
Unsteady (dynamic) part of the coefficient of singular input pressure losses.
♦ PDC_MOY_2 = cds
Stationary (average) part of the coefficient of singular output pressure losses.
♦ PDC_DYN_2 = cdsp
Unsteady (dynamic) part of the coefficient of singular output pressure losses.
Notes:
The values of the various mean and dynamic singular pressure loss coefficients are given, in addition, for various usual geometric input and output configurations (see below [§6]). |
|
By convention, a positive mean flow speed means that the flow occurs in the increasing direction of the space parameter along the axis of revolution of the structures. Conversely, a negative mean flow speed means that the flow is in the decreasing direction of the space parameter. The mean flow velocity sign therefore fixes the entry and exit positions. So that there is no ambiguity about these positions, care will be taken in CALC_FLUI_STRU [U4.80.03] to define a speed range with the same sign. |
|
Model MOCCA_COQUE used to solve fluid-structure coupling requires, for each mode selected, to identify the order of the shell on the deformed. Identifiable shell orders \({k}_{i}\) are such as: \({k}_{i}\le \frac{N}{2}\) where N designates the number of nodes in the mesh on a circumference, i.e. at a fixed altitude. Thes shell orders \({k}_{i}\) precisely identified are such as \({k}_{i}\le \frac{N}{4}\) , with the same definition for \(N\) . It is recommended to use a mesh with at least 20 knots on the circumferences of the shells. A minimum number of 8 knots is required. |
3.5. Keyword INFO#
◊ INFO = 1 or 2
Print level.
If INFO = 2 we print the characteristics of the configuration in the file MESSAGE.
If INFO = 1 printing step.