Buildings.Obsolete.Fluid.Movers

Name	Description
FlowMachinePolynomial	Fan or pump with head and efficiency declared by a non-dimensional polynomial
Examples	Package with obsolete models for examples of flow machines

Fan or pump with head and efficiency declared by a non-dimensional polynomial

Buildings.Obsolete.Fluid.Movers.FlowMachinePolynomial

Information

The normalized pressure difference is computed using a function of the normalized mass flow rate. The function is a polynomial for which a user needs to supply the coefficients and two values that determine for what flow rate the polynomial is linearly extended.

Note: This model is here for compatibility with older versions of this library. For new models, use instead Buildings.Fluid.Movers.FlowMachine_y.

Parameters

Connectors

Modelica definition

Type	Name	Default	Description
replaceable package Medium	PartialMedium	Medium in the component
Length	D		Diameter [m]
Real	a[:]		Polynomial coefficients for pressure=p(mNor_flow)
Real	b[:]		Polynomial coefficients for etaSha=p(mNor_flow)
Real	mNorMin_flow		Lowest valid normalized mass flow rate
Real	mNorMax_flow		Highest valid normalized mass flow rate
Real	scaM_flow	1	Factor used to scale the mass flow rate of the fan (used for quickly adjusting fan size)
Real	scaDp	1	Factor used to scale the pressure increase of the fan (used for quickly adjusting fan size)
Nominal condition
MassFlowRate	m_flow_nominal		Nominal mass flow rate [kg/s]
Initialization
MassFlowRate	m_flow.start	0	Mass flow rate from port_a to port_b (m_flow > 0 is design flow direction) [kg/s]
Pressure	dp.start	0	Pressure difference between port_a and port_b [Pa]
Assumptions
Boolean	allowFlowReversal	system.allowFlowReversal	= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
Advanced
MassFlowRate	m_flow_small	1E-4*abs(m_flow_nominal)	Small mass flow rate for regularization of zero flow [kg/s]
Diagnostics
Boolean	show_T	false	= true, if actual temperature at port is computed

Type	Name	Description
FluidPort_a	port_a	Fluid connector a (positive design flow direction is from port_a to port_b)
FluidPort_b	port_b	Fluid connector b (positive design flow direction is from port_a to port_b)
input RealInput	N_in	Prescribed rotational speed

model FlowMachinePolynomial "Fan or pump with head and efficiency declared by a non-dimensional polynomial" extends Buildings.Fluid.Interfaces.PartialTwoPortInterface; extends Modelica.Icons.ObsoleteModel; Modelica.Blocks.Interfaces.RealInput N_in "Prescribed rotational speed"; parameter Modelica.SIunits.Length D "Diameter"; parameter Real[:] a "Polynomial coefficients for pressure=p(mNor_flow)"; parameter Real[:] b "Polynomial coefficients for etaSha=p(mNor_flow)"; parameter Real mNorMin_flow "Lowest valid normalized mass flow rate"; parameter Real mNorMax_flow "Highest valid normalized mass flow rate"; parameter Real scaM_flow = 1 "Factor used to scale the mass flow rate of the fan (used for quickly adjusting fan size)"; parameter Real scaDp = 1 "Factor used to scale the pressure increase of the fan (used for quickly adjusting fan size)"; Real pNor(min=0) "Normalized pressure"; Real mNor_flow(start=mNorMax_flow) "Normalized mass flow rate"; Real etaSha(min=0, max=1) "Efficiency, flow work divided by shaft power"; Modelica.SIunits.Power PSha "Power input at shaft"; Medium.Density rho "Medium density"; protected parameter Real pNorMin1(fixed=false) "Normalized pressure, used to test slope of polynomial outside [xMin, xMax]"; parameter Real pNorMin2(fixed=false) "Normalized pressure, used to test slope of polynomial outside [xMin, xMax]"; parameter Real pNorMax1(fixed=false) "Normalized pressure, used to test slope of polynomial outside [xMin, xMax]"; parameter Real pNorMax2(fixed=false) "Normalized pressure, used to test slope of polynomial outside [xMin, xMax]"; initial equation Modelica.Utilities.Streams.print("The model Buildings.Fluid.Movers.FlowMachinePolynomial is deprecated. It will be removed in future releases. You should use Buildings.Fluid.Movers.FlowMachine_y instead of Buildings.Fluid.Movers.FlowMachinePolynomial."); // check slope of polynomial outside the domain [mNorMin_flow, mNorMax_flow] pNorMin1 = Buildings.Fluid.Utilities.extendedPolynomial( c=a, x=mNorMin_flow/2, xMin=mNorMin_flow, xMax=mNorMax_flow); pNorMin2 = Buildings.Fluid.Utilities.extendedPolynomial( c=a, x=mNorMin_flow, xMin=mNorMin_flow, xMax=mNorMax_flow); pNorMax1 = Buildings.Fluid.Utilities.extendedPolynomial( c=a, x=mNorMax_flow, xMin=mNorMin_flow, xMax=mNorMax_flow); pNorMax2 = Buildings.Fluid.Utilities.extendedPolynomial( c=a, x=mNorMax_flow*2, xMin=mNorMin_flow, xMax=mNorMax_flow); assert(pNorMin1>pNorMin2, "Slope of pump pressure polynomial is non-negative for mNor_flow < mNorMin_flow. Check parameter a."); assert(pNorMax1>pNorMax2, "Slope of pump pressure polynomial is non-negative for mNorMax_flow < mNor_flow. Check parameter a."); equation // For computing the density, we assume that the fan operates in the design flow direction. rho = Medium.density( Medium.setState_phX(port_a.p, inStream(port_a.h_outflow), inStream(port_a.Xi_outflow))); -dp = scaDp * pNor * rho * D*D * N_in * N_in; m_flow = scaM_flow * mNor_flow * rho * D*D*D * N_in; pNor = Buildings.Fluid.Utilities.extendedPolynomial( c=a, x=mNor_flow, xMin=mNorMin_flow, xMax=mNorMax_flow); etaSha = max(0.1, Buildings.Fluid.Utilities.polynomial( c=b, x=mNor_flow)); etaSha * PSha = -dp * m_flow / rho; // dp<0 and m_flow>0 for normal operation // Energy balance (no storage, no heat loss/gain) PSha = -m_flow*(port_a.h_outflow-inStream(port_b.h_outflow)); PSha = m_flow*(port_b.h_outflow-inStream(port_a.h_outflow)); // Mass balance (no storage) port_a.m_flow + port_b.m_flow = 0; // Transport of substances port_a.Xi_outflow = inStream(port_b.Xi_outflow); port_b.Xi_outflow = inStream(port_a.Xi_outflow); port_a.C_outflow = inStream(port_b.C_outflow); port_b.C_outflow = inStream(port_a.C_outflow); end FlowMachinePolynomial;