coupled thermo-electric vtb simulation model of cooling loop of a ship system
DESCRIPTION
Coupled Thermo-electric VTB Simulation Model of Cooling Loop of a Ship System. ESRDC Modeling and Simulation Workshop Tallahassee, FL 14 February, 2006. Jamil Khan, Ruixian Fang, A. Monti, Wei Jiang, University of South Carolina Greg Anderson, Mark Zerby, Phil Bernatos NSWC, Philadelphia. - PowerPoint PPT PresentationTRANSCRIPT
Coupled Thermo-electric VTB Simulation Model of Cooling Loop of
a Ship System
Jamil Khan, Ruixian Fang, A. Monti, Wei Jiang,
University of South Carolina
Greg Anderson, Mark Zerby, Phil Bernatos
NSWC, Philadelphia
ESRDC Modeling and Simulation Workshop Tallahassee, FL
14 February, 2006
Outline
• Problem Statement
• Models– Thermal– Electrical
• Simulation Results
• Conclusions
Problem Statement
Schematic for zone 2
Level 4
Level 3
Level 2
Level 1
FreshWater SeaWater HeatExchanger
FreshWater Heatsink HeatExchanger
Pipe
Pump
Valve
SeaWater
HeatSink
Temperature
mass flow
PCM board
Mixing model
2nd layer of Fw_HEX
Fresh Water- Sea Water Heat Exchanger
• Number of elements can be changed• Governing Eqns for each element:
L
L/120
Sea_Water Element #i
Tin
Conditions: m*h<=M where M is the mass of fluid of each element, as a special case, e.g., m*h=M , for each time step water in one element totally move into the next element.
22,_,_,_,_ tswhtavswtfwhtavfw
i
TTTTUAQ
htavfwfw
htfwfw
infw TM
hmT
M
hmT
_,__,, )1()(
Where ----Fresh water inlet temperature
----Fresh water temperature at time (t-h)
----Average fresh water mixing temperature at time (t-h)
----Mass flow rate
----time step
----Mass in control volume of each element
infwT ,
htfwT _,
htavfwT _,_
fwm
hfwM
htavswsw
swhtsw
sw
swinsw T
M
hmT
M
hmT
_,__,, )1()(
Where ----Fresh water temperature at time t
----Sea water temperature at time t
tfwT ,
tswT ,
htavfwtfwfwfw
i TTh
CMQ _,_,
htavswtswswsw
i TTh
CMQ _,_,
i
iQQ
fw
fw
M
hm
fw
fw
M
hm1
infwT ,htfwT _,
sw
sw
M
hm
infwT ,
sw
sw
M
hm1
htswT _,
Fresh water
Sea waterswm
inswT ,
iQ
Heat Sink
• Assume no temperature gradient along the length direction;
• Governing Eqns :
T1,Q1
T2,Q2
Qa
Q M CdT
d ta
We can also build this modal for several parts if necessary, that will take consider of the temperature difference along the length direction.
Where ----Inlet heat flow from heat source
---- Outlet heat flow from heatsink
---- heat absorbed by heatsink
21 QQQa
1Q
2Q
aQ
Where ----Mass of heatsink
---- Heatsink heat capacity
M
C
FreshWater- HeatSink Heat Exchanger
• Each model includes 12 elements;
• Governing Eqns for each element: The same logic used in this model as shown in Fresh water- Sea water
HeatExchanger
Conditions: m*h<=M where M is the mass of each element, as a special case, e.g., m*h=M , for each time step water in one element totally move into the next element.
m ,p m ,p
Tin Tout
Q,T
Element model
m1,p1 m2,p2
Tin T1,finalTav
#1 #2
Q1 Q2 Q3
#3
Q,T from heat sink
12
1iiQQ
22,_,_,, tfwhtavfwthshths
i
TTTTUAQ
htavfwtfwfwfw
i TTCh
MQ _,_,
htavfwfw
htfwfw
infw TM
hmT
M
hmT _,__,, )1()(
Where ----heatsink temperature at time t
---- heatsink temperature at time t-h
thsT ,
hthsT _,
Other models
Water Mixing Chamber Model
• Valid for 2 entering streams with different mass flow rate and temperature;
• Governing Eqns :
m1T1
m2
T2
m_outT_out
Pipe Model
• Mainly account for the pressure change caused by height elevation;
outouthmhmhm 2211
outoutTmTmTm 2211Which can be written as
Linear Valve Model
• Assume pressure drop linearly depends on the throttle opening.
Electrical System Model
• models can be seamlessly substitute to perform analysis Two different levels of details have been developed for the Electro-thermal model
• Those two with more or less focus on electrical system waveform
Model 1
• The electrical system is represented as a constant power load (the user can specify active and reactive power)
• The interaction with the thermal system is given by the efficient coefficient
• Any loss resulting from the efficiency calculation is supposed to be a forcing function for the thermal system
Model 1
Three-phase electrical terminal
Thermal port
Model 2
• The model includes the power electronics, the control and the electrical machine
• The power electronics is modeled through an averaged model
• Switching and conduction losses are estimated from the averaged model
Model 2
PEBB’s withThermal port
Control system
Induction machine
Controlled rectifier
4 PCM Heat Source
4 Heatsink Temperature
Example simulation results for PCM and Heatsink Model
Example simulation results for the freshwater-Seawater HeatExchanger
Fresh water inlet Temp.
Sea water outlet Temp.
Fresh water outlet Temp.
Example simulation results for the freshwater-Seawater HeatExchanger
Fresh water Temperature
Field
#120 Element
#110 Element
#100 Element
#10 Element
#20 Element
Length direction
Example simulation results for the freshwater-Seawater HeatExchanger
#120 Fresh water Temperature
#110 Fresh water Temperature
#100 Fresh water Temperature
#10 Fresh water Temperature
#20 Fresh water Temperature
Conclusions
• A real time coupled thermo-electrical simulation for slice 2 of DDG-51 has been successfully developed in VTB
• The simulation couples electrical and thermal models• Results have been validated with experimental data• The simulations can be extended to include chillers• Transient responses to changing loads can be
studied – Simulation is available for demonstration