PAT312, Section 45, December 2006 S45-1 Copyright 2007 MSC.Software Corporation SECTION 45 HYDRAULIC NETWORKS

PAT312, Section 45, December 2006 S45-2 Copyright 2007 MSC.Software Corporation

PAT312, Section 45, December 2006 S45-3 Copyright 2007 MSC.Software Corporation FLOW NETWORKS l When the mass flow rates in a flow circuit are unknown you can use the MSC.Thermal flow network solver to compute these mass flow rates and subsequently use these flow rates in the thermal calculation l Currently, only steady and quasi – steady – state, incompressible, single phase flow is supported l Pipe, turbine, pump, head loss, check valve, plenum elements can be modeled

PAT312, Section 45, December 2006 S45-4 Copyright 2007 MSC.Software Corporation FLOW NETWORKS ONE DIMENSIONAL FLOW NETWORK l Flow networks are incorporated into MSC.Thermal to analyze the complex fluid flow system coupled with the heat transfer problem. l The analysis is focused on average flow parameters l Mass flow rate and Pressure l More detailed analysis of the flow field requires a CFD solver l Assumptions: 1. The flow is incompressible, single phase with no viscuous heating 2. Physical and material properties are constant over the element. They can vary from element-to-element and can be time and/or temperature dependent 3. Flow is steady state or quasi-steady state. (steady state at each transient point)

PAT312, Section 45, December 2006 S45-5 Copyright 2007 MSC.Software Corporation FLOW NETWORK DARCY-WEISBACH EQUATION P = static pressure in the duct = fluid mass density f = moody friction factor V = Fluid mean velocity D = Hydraulic diameter of the flow passage L = Length of flow passage from node I to J Casting this equation in terms of mass flow rate Linearizing the above equation the following is obtained: The pressure drop in a fluid flowing in a duct from I to J can be expressed as:

PAT312, Section 45, December 2006 S45-6 Copyright 2007 MSC.Software Corporation DARCY-WEISBACH EQUATION (Cont.) Adding the head losses in flow with the loss coefficient, K Adding gravity and pump/turbine heads the basic equation in matrix form can be written as

PAT312, Section 45, December 2006 S45-7 Copyright 2007 MSC.Software Corporation ONE DIMENSIONAL FLOW NETWORK (Cont.) K p = pressure conductivity matrix P = nodal static pressure = fluid mass flow rate The flow resistance is a function of pressure and therefore the problem is nonlinear and an iterative procedure is required for solution. The resistances are computed, assembled and the matrix equations are solved for nodal pressures.

PAT312, Section 45, December 2006 S45-8 Copyright 2007 MSC.Software Corporation FLOW NETWORKS PRESSURE BOUNDARY CONDITION l Pressure is applied to the nodes l At least 1 pressure LBC must be applied l Four options available for pressure boundary condition l Fixed l Time Table l Initial l Template l For Template pressure, the positive integer template ID points into template.dat.apnd file. The pressure macro is similar to temperature or heat macro. Can optionally enter a pressure multiplier.

PAT312, Section 45, December 2006 S45-9 Copyright 2007 MSC.Software Corporation FLOW NETWORKS MASS FLOW RATE BOUNDARY CONDITION l Enter a constant Mass Flow Rate or l Enter a Template ID l Template ID will point into template.dat.apnd file l Use MACRO template l Template is used to assign a functional variation of Mass Flow Rate l Use Field/NonSpatial/General to write function l Independent variable Temperature = Pressure l If both TID and Mass Flow Rate are specified, the Mass Flow Rate specified is taken as a scale factor on the value returned by the Mass Flow Template l The Mass Flow Template is similar to temperature/heat/pressure macro template

PAT312, Section 45, December 2006 S45-10 Copyright 2007 MSC.Software Corporation FLOW NETWORK ELEMENT PROPERTIES AND OPTIONS l The input data form will vary according to the option selected (Turbine, Pipe, check valve, etc.) l Enter a fluid Template ID l Enter the flow element option l IOPT = 1 for constant properties pipe element l If required by the IOPT the TID entered here will point into template.dat l Enter pipe properties l Enter pipe length l If the pipe length is not specified, the node to node distance will be used

PAT312, Section 45, December 2006 S45-11 Copyright 2007 MSC.Software Corporation l Input loss coefficient. This can represent head loss in pipe bends, valves, fittings, etc. l Enter the CONSTANT fluid density, viscosity, specific heat. If these properties are not constant they have to be defined with MPIDs in the template.dat file and appropriate element option (IOPT) has to be chosen. l Enter friction factor. If friction factor is unknown, use IOPT – 2 and MSC.Thermal will compute the friction factor from Moodys FLOW NETWORK ELEMENT PROPERTIES AND OPTIONS

PAT312, Section 45, December 2006 S45-12 Copyright 2007 MSC.Software Corporation HYDRAULIC (FLOW NETWORK) INPUTS l Under analysis pick from the top level menu, input the data needed in the flow network (hydraulic) solution

PAT312, Section 45, December 2006 S45-13 Copyright 2007 MSC.Software Corporation HYDRAULIC (FLOW NETWORK) INPUTS (Cont.) l Select Hydraulic Analysis or Coupled Thermal – Hydraulic Analysis as the Solution Type

PAT312, Section 45, December 2006 S45-14 Copyright 2007 MSC.Software Corporation HYDRAULIC (FLOW NETWORK) INPUTS l When you click on Solution Parameters, the following form will be displayed l Only the Direct Solver is supported for hydraulic networks at present l Input number of iterations between hydraulic solutions. For Steady State, this is the number of steady state iterations. For transient solutions, this is the number of time steps.

PAT312, Section 45, December 2006 S45-15 Copyright 2007 MSC.Software Corporation HYDRAULIC FLOW NETWORKS INPUTS l When you click on Hydraulic / Run Control Parameters button, the following form is displayed: l Needed for calculating turbine/pump heads l Enter gravitational acceleration in X,Y,Z directions. Needed to compute gravity heads in piping networks

PAT312, Section 45, December 2006 S45-16 Copyright 2007 MSC.Software Corporation ELEMENT OPTIONS & FLUID TEMPLATES l Pipe, turbine, pump, head loss, check valve, and plenum elements are supported l Options available on Element Properties / Flow Network form l Sub options are available l Input in the IOPT data box

PAT312, Section 45, December 2006 S45-17 Copyright 2007 MSC.Software Corporation HYDRAULIC ELEMENT OPTIONS PIPE IOPT / Option 1:Constant physical and material properties. Input DataTID / IOPT / DIAM / CSAA / PERIM / LENGTH / ROUGHNESS / LOSS_COEFF / DENSITY / VISCOSITY / SPECIFIC_HEAT / FRICTION_FACTOR / COEFF_Thermal_Expansion IOPT / Option 2:Constant physical and material properties. Friction factor evaluated by MSC.Thermal Moody Equation. Input DataTID / IOPT / DIAM / CSAA / PERIM / LENGTH / ROUGHNESS / LOSS_COEFF / DENSITY / VISCOSITY / SPECIFIC_HEAT / COEFF_Thermal_Expansion IOPT / Option 3:Constant physical properties, MPID defined (variable) material properties. Requires template definition. Input DataTID / IOPT / DIAM / CSAA / PERIM / LENGTH / ROUGHNESS / LOSS_COEFF

PAT312, Section 45, December 2006 S45-18 Copyright 2007 MSC.Software Corporation HYDRAULIC ELEMENT OPTIONS FLUIDTID#MPIDs IOPT MPID_THO MPID_MU MPID_CP MPID_LOSS_COEFF MPID_COEFF_Thermal_Expansion MPID If MPID_F is zero, then friction factor evaluated by MSC.Patran Thermal Moody Equation. Else, friction factor evaluated by MPID function. PUMP IOPT / Option 4:Constant properties and constant head pump. Head cannot go negative. Input DataTID / IOPT / DENSITY / VISCOSITY / SPECIFIC_HEAT / HEAD IOPT / Option 5:MPID defined properties and variable head pump. Head cannot go negative. Input DataTID / IOPT FLUIDTID#MPIDs IOPT MPID_RHO MPID_MU MPID_CP MPID_Head in mat.dat..apnd file in mat.dat.apnd file

PAT312, Section 45, December 2006 S45-19 Copyright 2007 MSC.Software Corporation TURBINE IOPT / Option 6:Constant properties and constant head turbine. Head cannot go positive. Input DataTID / IOPT / DENSITY / VISCOSITY / SPECIFIC_HEAT / HEAD IOPT / Option 7:MPID defined properties and variable head turbine. Head cannot go positive. Input DataTID / IOPT FLUIDUID#MPIDs IOPT MPID_RHO MPID_MR MPID_CP MPID_HEAD LOSS ELEMENT or CONTROL VALVE IOPT / Option 8:Variable geometry and variable head loss. Input DataTID / IOPT / DIAM / CSAA / PERIM / LENGTH / ROUGHNESS / LOSS_COEFF in mat.dat.apnd file HYDRAULIC ELEMENT OPTIONS

PAT312, Section 45, December 2006 S45-20 Copyright 2007 MSC.Software Corporation FLUIDTID# MPID's IOPT MPID_DIAM MPID_RHO MPID_MU MPID_CP MPID_EPS MPID_LOSS_COEFF MPID_COEFF_Thermal_Expansion MPID-F Note: The geometric values will be used as scale factors on the values obtained from the material property evaluations. CHECK VALVE IOPT/Option 9:Constant physical and material properties. Input Data TID / IOPT / DIAM / CSAA / PERIM / LENGTH / ROUGHNESS / LOSS_COEFF / DENSITY / VISCOSITY / SPECIFIC_HEAT / COEFF_Thermal_Expansion If the flow is not from Node 1 to Node 2, the diameter is set to 0. Friction factor is evaluated by MSC.Patran Thermal. IOPT/Option 10:Constant geometry and variable material property. Input Data TID / IOPT / DIAM / CSAA / PERIM / LENGTH / ROUGHNESS / LOSS_COEFF in mat.dat.apnd file HYDRAULIC ELEMENT OPTIONS

PAT312, Section 45, December 2006 S45-21 Copyright 2007 MSC.Software Corporation FLUIDTID#MPIDs IOPT MPID_RHO MPID_MU MPID_CP MPID_LOSS_COEFF MPID_COEFF_Thermal_Expansion MPID-F Note: The geometric values input will be used as scale factors on the values obtained from the material property evaluations. PLENUM IOPT/Option 11:Plenum constant physical and material properties. Input DataTID / IOPT / DENSITY / VISCOSITY / SPECIFIC_HEAT IPOT/Option 12:Plenum with variable material properties. Input DATATID / IOPT FLUIDTID#MPIDs IOPT MPID_RHO MPID_MU MPID_CP MPID_LOSS_COEFF MPID_COEFF_Thermal_Expansion MPID-F in mat.dat.apnd file HYDRAULIC ELEMENT OPTIONS

PAT312, Section 45, December 2006 S45-22 Copyright 2007 MSC.Software Corporation HYDRAULIC NETWORK RESULTS l After a successful hydraulic network run nhxxx.nrf, npxxx.nrf, qout.dat file will be created in the jobname directory l npxxx These are MSC.Patran pressure nodal results files that Q/TRAN generates for hydraulic nodes. Two values can be put in this file, pressure and net nodal mass flow rate. One np file is generated per Q/TRAN print dump. l nhxxx These are MSC.Patran hydraulic element files that Q/TRAN generates for the hydraulic (flow) network. Four values can be put in this file which represent elemental quantities; Mass flow rate, Differential head, Fluid velocity, and Volumetric flow rate. In addition, the entrance and exit node number of element is specified. One nh file is generated per Q/TRAN print dump. l Both np and nh files can be output in binary or ASCII format.

PAT312, Section 45, December 2006 S45-23 Copyright 2007 MSC.Software Corporation

PAT312, Section 45, December 2006 S45-24 Copyright 2007 MSC.Software Corporation