AGA3.py

# -*- coding: utf-8 -*-
"""
Created on Fri Aug 27 09:16:20 2010

@author: g.junqueira

AGA3 METER GAS CALCULATION IMPLEMENTATION as a callable Python function
"""
import math


def AGA3 (DP, Tf, Pf, DFLOW, Dr, ALPHA2,ALPHA1=0.00000925,Tr=60.0, Pb=14.73):
    """
    Inputs:
    DP = Differential pressure, in Inches H2O
    Tf = Flowing Temperature Meter, in Deg. F.
    Pf = Flowing Pressure meter, in psig
    Tb = Base temprature, in Deg. F. (60 deg. F , as defined in USC)
    Pb = Base pressure, in psia (14.73psia, as defined in USC)
    Dr = reference orifice plate bore diameter at Tr, in inches
    ALPHA1 = linear coefficient of thermal expansion for orifice plate material, in in/in-DegF
                  carbon steel (0.00000620), 304 or 316 stainless (0.00000925), 
                  monel (0.00000795), Hastalloy C (0.0000063)
                  
              
    """
          
    return 0
          
def __orifBore(Dr, Tf, ALPHA1=0.00000925, Tr=60.0):
    """
    calculates orifice bore diameter at  flowing conditions (d)
    
    """
    d = Dr*(1.0 + ALPHA1*(Tf-Tr))
    
    
    return (d)
    
def __pipeIntDiam (Dr, ALPHA2, Tf, Tr=60.0):
    """
    
    """
    D = Dr*(1.0 + ALPHA2*(Tf-Tr))
    
    return (D)
    

def __velOfApproach (d, D):
    """
    
    """
    __Beta = d/D
    __Beta2 = math.pow(__Beta, 4.0)
    
    Ev = 1.0/(math.sqrt((1.0-__Beta2)))
    
    return (Ev)
    
def __unitConversion (unit=0):
    """
    0 = U.S
    1 = IP
    2 = Metric
    3 = SI
    
    """
    __const0 = 3.232790 * math.pow(10.0, 2.0)
    __const1 = 4.655210 * math.pow(10.0, 4.0)
    __const2 = 3.600 * math.pow(10.0,-2.0)
    __const3 = 1.0
    if unit ==1:
        N1 = __const1
    elif unit ==2:
        N1 = __const2
    elif unit ==3:
        N1 = __const3
    else:
        N1 = __const0
        
    return (N1)