#cls
text(resistances and tube flow in heat exchanger
title
libref=710
DISPLAY
This In-Form case mimics PLANT case Z110, in three respects:
(1) heat-transfer and friction resistances are represented by
source formulae;
(2) the heat transfers between the two fluids are represented by
formulae containing the difference between their temperatures;
and
(3) use of the built-in 'neighbour technique' for tube-side flow
is replaced by use of source formulae.
The friction coefficient depends upon the symmetrically-computed
velocity-squared quantity which is stored as the VLSQ variable.
Users are advised to vary such input data as FLO1, FLO2 and COEF12
so as to understand their influences on the temperature fields.
It should be noted that the grid is coarse and that the 5-pass
tube-side flow is not typical of real heat exchangers; nor are the
resistance formulae realistic.
These features appear only because case z110 was devised to show
how the first-ever 3D-heat-exchanger simulation of Patankar and
Spalding (1974) can now be handled by PHOENICS.
ENDDIS
PHOTON USE
p;;;;;
up 1 0 0;vi 0.5 1 0.75
gr ou x 1;gr ou y 1;gr ou z 1
gr ou x m;gr ou y m;gr ou z m
gr ou x 1 y 1 2 z 2 2 col 2
gr ou x 6 y 1 2 z 7 7 col 2
gr ou z 4 x 1 4 y 1 3 col 6
gr ou z 6 x 2 5 y 1 3 col 6
ve y 2 sh
msg 3D SHELL-AND-TUBE HEAT EXCHANGER
msg --------------------------------
msg Shell-side velocity vectors
msg Press Enter to continue
pause;vi 0 1 0
msg 3D SHELL-AND-TUBE HEAT EXCHANGER
msg --------------------------------
msg Shell-side temperature contours
con shlt y 2 fi ; 0.001
msg Press Enter to continue
pause
con off;red
msg 3D SHELL-AND-TUBE HEAT EXCHANGER
msg --------------------------------
msg Tube-side temperature contours
con tubt y 2 fi ; 0.001
msg Press e to END
ENDUSE
load(z110)
Settings in z110 which it mat be interesting to modify
Here 1 refers to the shell-side fluid and 2 to the tube-side fluid
The units are arbitrary
T1IN=1.0; T2IN=0.0 ! temperatures
FLO1=0.1; FLO2=0.1 ! flow rates
COEF1=0.1; COEF2=0.4 ! heat-transfer coefficients
COEF12=1.0/(1.0/COEF1+1.0/COEF2)
RESCO=1.E2 ! tube-bank flow-resistance coefficient
LIBREF=710
COEF12=0.01 ! vary this to show influence of overall heat-transfer
! coefficient
COEF12
INFORM13BEGIN
** The next lines de-activate PLANT sources **
NAMSAT=NONE
HEX=SKIP
** The next lines de-activate neighbour technique **
NEH1=SKIP
NEW1=SKIP
NEL1=SKIP
NEW2=SKIP
NEH2=SKIP
NEW3=SKIP
NEL2=SKIP
NEW4=SKIP
NEH3=SKIP
name(14)=shlt;name(15)=tubt
West boundary; shell fluid inlet ; 2 cells in west wall
PATCH(SHELLIN,CELL,1,1,2,3,2,2,1,1000) ! small patch in west wall
! change to the following in order to remove 3D effects so that
1 the y-independence of the solution can be checked
PATCH(SHELLIN,CELL,1,1,1,3,2,2,1,1000)
COVAL(SHELLIN,P1,FIXFLU,FLO1/2.0); COVAL(SHELLIN,shlt,ONLYMS,T1IN)
East boundary; shell fluid outlet; 2 cells in east wall
PATCH(SHELLOUT,EAST,NX,NX,2,3,NZ-1,NZ-1,1,1000) ! patch in east wall
! change to the following in order to remove 3D effects so that
1 the y-independence of the solution can be checked
PATCH(SHELLIN,CELL,1,1,1,3,2,2,1,1000)
COVAL(SHELLOUT,P1,FIXP,0.0)
** The symmetrically-computed velocity-squared quantit
STORE(VLSQ)
LSWEEP=200
** The following In-Form formulae replace actions
of the neighbour technique **
REAL(FLOW); FLOW=FLO2/3.0
** Flow of tube fluid in first pass **
PATCH(INEH1,CELL,1,1,1,NY,1,NZ-1,1,1000)
(SOURCE tubt at INEH1 is FLOW*(tubt[,,+1]-tubt) with LINE)
The equivalent of it is the following In-Form statement
(SOURCE tubt at INEH1 is FLOW*(HIGH(tubt)-tubt) with LINE)
** Flow of tube fluid in first bend **
PATCH(INEW1,CELL,2,2,1,NY,1,1,1,1000)
(SOURCE tubt at INEW1 is FLOW*(tubt[-1]-tubt) with LINE)
** The equivalent of it is the following In-Form statement
(SOURCE tubt at INEW1 is FLOW*(WEST(tubt)-tubt) with LINE)
** Flow of tube fluid in second pass **
PATCH(INEL1,CELL,2,2,1,NY,2,NZ,1,1000)
(SOURCE tubt at INEL1 is FLOW*(tubt[,,-1]-tubt) with LINE)
** The equivalent of it is the following In-Form statement
(SOURCE tubt at INEL1 is FLOW*(LOW(tubt)-tubt) with LINE)
** Flow of tube fluid in second bend **
PATCH(INEW2,CELL,3,3,1,NY,NZ,NZ,1,1000)
(SOURCE tubt at INEW2 is FLOW*(tubt[-1]-tubt) with LINE)
** The equivalent of it is the following In-Form statement
(SOURCE tubt at INEW2 is FLOW*(WEST(tubt)-tubt) with LINE)
** Flow of tube fluid in third pass **
PATCH(INEH2,CELL,3,3,1,NY,1,NZ-1,1,1000)
(SOURCE tubt at INEH2 is FLOW*(tubt[,,+1]-tubt) with LINE)
** The equivalent of it is the following In-Form statement
(SOURCE tubt at INEH2 is FLOW*(HIGH(tubt)-tubt) with LINE)
** Flow of tube fluid in third bend **
PATCH(INEW3,CELL,4,4,1,NY,1,1,1,1000)
(SOURCE tubt at INEW3 is FLOW*(tubt[-1]-tubt) with LINE)
** The equivalent of it is the following In-Form statement
(SOURCE tubt at INEW3 is FLOW*(WEST(tubt)-tubt) with LINE)
** Flow of tube fluid in fourth pass **
PATCH(INEL2,CELL,4,4,1,NY,2,NZ,1,1000)
(SOURCE tubt at INEL2 is FLOW*(tubt[,,-1]-tubt) with LINE)
** The equivalent of it is the following In-Form statement
(SOURCE tubt at INEL2 is FLOW*(LOW(tubt)-tubt) with LINE)
** Flow of tube fluid in fourth bend **
PATCH(INEW4,CELL,NX,NX,1,NY,NZ,NZ,1,1000)
(SOURCE tubt at INEW4 is FLOW*(tubt[-1]-tubt) with LINE)
** The equivalent of it is the following In-Form statement
(SOURCE tubt at INEW4 is FLOW*(WEST(tubt)-tubt) with LINE)
** Flow of tube fluid in fifth pass **
PATCH(INEH3,CELL,NX,NX,1,NY,1,NZ-1,1,1000)
(SOURCE tubt at INEH3 is FLOW*(tubt[,,+1]-tubt) with LINE)
** The equivalent of it is the following In-Form statement
(SOURCE tubt at INEH3 is FLOW*(HIGH(tubt)-tubt) with LINE)
** In-Form formulae which are equivalent to the
PLANT formulae of z110 **
PATCH(IHEX,VOLUME,1,NX,1,NY,1,NZ,1,1000)
(SOURCE of shlt at IHEX is :coef12:*VLSQ^0.25*(tubt-shlt) with LINE)
(SOURCE of tubt at IHEX is :coef12:*VLSQ^0.25*(shlt-tubt) with LINE)
INFORM13END
XZPR=T
DISTIL=T
ITABL=2
EX(SHLT)=7.014E-01; EX(TUBT)=2.785E-01; EX(VLSQ)=4.007E-01
EX(HPOR)=5.000E-01; EX(NPOR)=5.000E-01; EX(EPOR)=5.000E-01
#conprom
#endpause
#maxabs