InterfaceUnit - Kernel expression

For some components it is possible to specify an EbsScript function instead of one or more default values, in which the corresponding value is calculated.

This function must have the name "evalexpr" and assign the desired value to a real variable "evalexpr". The names of these default values usually begin with an "E" (examples: EMATT, EALPH12, EFCWIND).

Before this possibility existed, only one default value of a component could be replaced by a function or formula with the help of ADAPT / EADAPT.

For some KernelExpressions, some additional internal values from the current calculation step are available. They can be accessed with functions from this unit. For example, they can be listed with the function ksGetInternals.

Example

function evalexpr:REAL;

begin

     evalexpr:=0.01;

end;

For the “Kernel expressions“, there are some special data types and functions that can be found in the EbsScript interface unit @KernelExpression:

Functions

Name	Purpose	Arguments	Return value	Example
keGetComp	returns the component just calculated (as “ebscomp”)	-	ebsComp:	function evalexpr: REAL; var eComp:ebscomp; eVar:ebsvar; str, strName:string; ar:array of InternalValue; i,n:integer; r:real; begin eComp:=keGetComp; eVar:=keGetKernelExpression; getName(eVar, strName); ar:=keGetInternals; n:=Length(ar); str:=printToString (eComp," ",strName," ",n,"\n"); for i:=0 to (n-1) do begin str:=printToString (str,ar[i].name," ",ar[i].value,"\n"); end; if (keGetInternalVar("PHIINC", r)) then begin str:=printToString (str,"PHIINC is ",r,"\n"); end; r:=keGetInternal("TAVER"); str:=printToString (str,"TAVER is ",r,"\n"); messagebox (str); end;
keGetInternals	yields a field with additional internal quantities available for calculating the specification value (component-specific)	-	array of InternalValue
keGetInternal	returns the value of one of these additional variables as a function value, in the event of an error, the value specified under on_error_return.	1: STRING: 2: REAL	REAL: Value of the internal variable
keGetInternalVar	allows the query of a value of one of these additional quantities and yields back the status of this query	1: STRING: 2: REAL	BOOLEAN:
keGetItNo	yields the number of the actual iteration step	-	INTEGER:
keGetKernelExpression	returns a reference to the currently calculated ebs value (updates will not take effect until the next simulation)	-	ebsVar
keGetIndicatedValue	Returns the specified values of components 45 without returning from the calculation status (for use in expressions)	1.INTEGER: Index of component 45 2: REAL: on_error_return (optional )	REAL: Value of component 45
keGetIndicatedValueByObject	returns the value of the components 45 for the given reference (EBSCOMP45) without returning from the calculation status (for use in expressions)	1: EBSCOMP45 the reference to Comp. 45 2: REAL: on_error_return (optional )	REAL: Value of component 45
keGetIndicatedValueByObjectVar	returns the value of the components 45 for the given reference (EBSCOMP45) and the calculation status	1: EBSCOMP45 the reference to Comp. 45 2: REAL: Value of component 45	BOOLEAN: Status of execution true, if successful, otherwise false
keGetIndicatedValueVar	returns the specified values of components 45 and returns the calculation status	1.INTEGER: Index of component 45 2: REAL: Value of component 45	BOOLEAN: Status of execution true, if successful, otherwise false
Procedures:
keSetComment	Output of comments, that are displayed in the error list	1.STRING: commentary text	-
keSetError	Output of errors, that are displayed in the error list. Calling keSetError with abortCalculation = true will abort the running simulation	1.STRING: error text 2.BOOLEAN: abort Calculation Flag	-
keSetWarning	Calling keSetError with abortCalculation = true will abort the running simulation	1: STRING: warning	-

List of internal quantities available in certain KernelExpression default values of a component (as of 11.2021):

Component number, followed by the available internal variables

7: T_WALL VF

9: T_WALL

10: T_WALL VF

11: COSPHI H2P GENF

12: TARGET ACTUAL   CORRECTION   ERRORLEVEL
39: TARGET ACTUAL   CORRECTION   ERRORLEVEL
69: TARGET ACTUAL   CORRECTION   ERRORLEVEL

20: T_WALL

21: RATCOS TBED

83: ROTSPEED

89: PH2O_FLUEGAS XASH_FLUEGAS T_FLUEGAS P_FLUEGAS M_FLUEGAS
    T_WALL THLAY CSASH DIAASH
    DISTASH FUELTYPE M_FUEL_WAF PERCCOKE CSCOAL
    DIACOAL DISTCOKE SOOTCONT ETA_FLUEGAS
    CP_FLUEGAS LAMBDA_FLUEGAS LAMBDA_FIN WIDTH_FGDUCT DEPTH_FGDU
    CT RHO_FLUEGAS RHOIN_FLUEGAS RHOOUT_FLUEGAS

90: RCATOS TBED TAD_FLUEGAS_KELVIN TOUT_FLUEGAS_KELVIN

113: PHIINC PHITRAN TAVER TAMB DNI VWIND AWIND
116: PHIINC PHITRAN TAVER TAMB DNI VWIND AWIND

119: T_WALL T_FLUID

120: TAVER TAMB VWIND AWIND

121: RSHEIGHT RSAZIM RDNI VWIND AWIND

126: T_BWALL T_OWALL

160: T_WALL

More Examples

function evalexpr:REAL;


// result must be in m³/m³ if FCON=1, in mg/Nm³ if FCON=2


var myComp:ebsComp21;
begin
    myComp:=ebscomp21(keGetComp());
    if (myComp.ALAM < 1.1 and Fluegas.T > 1000 ) then begin
        evalexpr:=Fluegas.T-1000;
    end else begin
        evalexpr:=0.0;
    end;
end;

function evalexpr:REAL;
var
  eVar:ebsvar; eComp:ebscomp;
  eComp83:ebscomp83;
  str, strName:string;
  ar:array of InternalValue;
  i,n:integer;
  r,g,x:real;

begin

  eComp   := keGetComp;
  eComp83 := ebscomp83(ecomp);
  eVar    := keGetKernelExpression;
  getName (eVar, strName);
  ar  := keGetInternals;
  n   := Length(ar);
  str := printToString (strName," (",n);
  keGetInternalVar ("ROTSPEED", r);  
  g := r / ecomp83.REVN;
  if keGetItNo() = 6 then begin
     str := printToString (str,") ROTSPEED is ",r, " ", g," ", log(g),"\n");
     print (str);
  end;

  if (g > 1.0) then begin
     x := 0.99;
     println ("x1:", x);
     evalexpr := x;
  end else begin
     x := ((0.0367 * log(g)) + 0.9898);
     println ("x2:", x);
    evalexpr := x;
  end;

end;

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