VUFF

The VUFF file contains the model geometry elemental properties written by ECHOS, the view factors, heat flux view factors, solar view factors, albedo factors, and Earth view factors written by VUFAC, and the IR and solar spectrum gray body view factor matrices written by GRAYB.

The written content is always appended to VUFF.

MNM, I, J, AR, E, TSA, VF, TIME, DD

MNM = the mnemonic code for the Card. All Cards except for MNM = NGR, MNM = AXM, and MNM = RDF can be read with the format (A3,2I6,3E11.4,F11.7,2E11.4).

  • MNM = AXM for expansion of axisymmetric profile elements written by the DATACH module. MNM = AXM can be read with the format (A3,10I6).
  • MNM = ALB for albedo factors written by the VUFAC module.
  • MNM = ALR for albedo factors calculated with ray-tracing written by the VUFAC module.
  • MNM = BVF for view factors written by the VUFAC module.
  • MNM = EVF for Earth view factors written by the VUFAC module.
  • MNM = EVM for Earth view factors modified values when the value of PIRSUBSOLAR > PIR.
  • MNM = EVR for Earth view factors calculated with ray-tracing written by the VUFAC module.
  • MNM = GRD for node coordinates X, Y, Z written by the ECHOS module.
  • MNM = HVF for solar spectrum heat flux view factors written by the VUFAC module.
  • MNM = HVI for IR spectrum heat flux view factors written by the VUFAC module.
  • MNM = IGM for the IR spectrum gray body view factor matrix.
  • MNM = NCC for the element center for circular elements written by the ECHOS module.
  • MNM = NCG for the element's C.G written by the ECHOS module.
  • MNM = NDC for the element center for non-circular elements written by the ECHOS module.
  • MNM = NGR for the node numbers for an element written by the ECHOS module. MNM = NGR can be read with the format (A3,10I6).
  • MNM = NPR for the elemental properties written by the ECHOS module.
  • MNM = NRM for the element's surface normal written by the ECHOS module. For beam elements MNM = NRM is the axial unit vector pointing from node 1 to node 2.
  • MNM = SVF for solar view factors written by the VUFAC module.
  • MNM = SGM for the solar spectrum gray body view factor matrix.
  • MNM = RDF for run definition Cards.
  • MNM = REV for reverse elements written by the DATACH module.

At the start of each run, a run definition card written by the MAIN module containing the run title and date is written in the format ('RDF',A80).

The Card 9 NAME group names, starting element, increment, and ending element, and group name number are written on file VUFF by the DATACH module with the format ('RDFGROUPNAMES',1X,A7,I9,I12,2I10).

The Card 9 VARIABLE symbolic variable names and values are written on file VUFF by the DATACH module with the format ('RDFVARIABLENAME',1X,A31,E15.8).

I is:

  • I = element from, or
  • I = blank for nodes.
  • I = the profile element number for MNM = AXM.

J is:

  • J = blank, or
  • J = element to, or
  • J = element number of the radiative source for heat flux view factors, or
  • J = node number for GRD.
  • J = the number of nodes for NGR.
  • J = the first expanded element number for MNM = AXM. The fourth field represents the last expanded element number, and the fifth field represents the increment.
  • J = the reverse element number for MNM = REV.

AR is:

  • AR = area or volume of element I, or
  • AR = X coordinate for GRD, NDC, NCG, NCC, or NRM.

E is:

  • E = emissivity of element I.
  • If E = -2.34, the element is recognized by the VUFAC module for area-proportional conductance calculations, but not for radiation.
  • If E < 0, it is not recognized by the VUFAC module at all.
  • If E = -1.23, it is assigned an area = 0.
  • E = Y coordinate for GRD, NDC, NCG, or NRM.

TSA is:

  • TSA = TSA parameter (combined radiative solar spectrum property) of element I.
  • TSA = Z coordinate for GRD, NDC, NCG, NCC, or NRM.

VF is:

  • VF = view factor from I to J if MNM = BVF and MNM = HVF and TIME = -1.E36
  • VF = gray body view factor from I to J if MNM = SGM or IGM
  • VF = solar view factor if MNM = SVF
  • VF = albedo factor if MNM = ALB
  • VF = Earth view factor if MNM = EVF
  • VF = thermal conductivity times cross-sectional area, or thermal conductivity times thickness, or thermal conductivity (for solid elements) of element I if MNM = NPR
  • VF = -1E30 if MNM = NPR for elements that are the reverse sides of other elements created by the Card 9 REVNODE, and for SPACE elements created with Card 5d.

This ensures that follower conductances are created to recover the temperatures of these elements after they are merged.

If VF < -1.E28, and MNM = NPR, then the element I is not recognized by the COND module for conduction calculations.

TIME is:

  • TIME = time at which the view factor (MNM = BVF), solar view factor (MNM = SVF), Earth view factor (MNM = EVF), heat flux view factor (MNM = HVF), or albedo factor (MNM = ALB) occurs.
  • TIME is = -1.E36, -1.1E36, or -1.2E36 for view factors (MNM = BVF) that will be used only for radiative conductance and gray body view factor calculations and are constant over time.
  • TIME = -1.1E36 on a BVF Card is a flag indicates that the view factor was calculated with ray-tracing using the solar spectrum surface properties. The value in the AR field is equal to the area of the element multiplied by the factor (1-solar spectrum specularity/transparency). The values in the E and TSA fields are equal to the emissivity and absorptivity of the element divided by the factor 1/(1-solar spectrum specularity/transparency) respectively. If no IR spectrum properties were specified for the model, the view factors of this Card are considered valid for both the solar and IR spectra. If IR spectrum properties were calculated for the model, the view factors of this Card are considered valid for the solar spectrum only.
  • TIME = -1.2E36 is a flag indicates that the view factor was calculated with ray-tracing using the IR spectrum surface properties. The value in the AR field is equal to the area of the element multiplied by the factor (1-IR spectrum specularity/transparency). The values in the E and TSA fields are equal to the emissivity and absorptivity of the element divided by the factor 1/(1-IR spectrum specularity/transparency) respectively.
  • TIME = -1.E36 for gray body view factors (MNM = SGM and MNM = IGM).
  • TIME = specific heat*density value of for solid element I, or specific heat*density*thickness value for planar element I, or specific heat* density*cross-sectional area for beam element I if MNM = NPR.

DD is:

  • DD = hydraulic diameter of the element for MNM = NPR.
  • DD = shadowing flag if MNM = BVF.
  • DD = 0 if the view factor was calculated with shadowing.
  • DD = 1 if it was calculated without shadowing.