Challenge

Data analysis- File Parsing of IC Engine Simulation Data using PYTHON

JJayaram Talabattula15 Jan 2021

PYTHON

FILE PARSING AND PLOTTING OF IC ENGINE SIMULATION DATA

AIM:

Write a program in PYTHON to parse a thermodynamic file and plot the desired results.
The program should automatically ask the user for column numbers, print and save the plots.

OBJECTIVES OF THE PROJECT:

A set of commands were used to access the file and extract the desired column names and simulation values.
A function was created for the computation of power output and specific fuel consumption.
The desired column plots and PV graph was plotted and saved.
The area under the PV curve was computed using a function.

BODY OF THE CONTENT:

Code:

import math
import matplotlib.pyplot as plt
import numpy as np

"""
Program to parse IC Engine simulation data and plot the output of desired parameters
"""

#Function for Area under the PV Curve and Power Output of Simulation Cycle
def powerfunc(rpm,x_data,y_data):
	area=np.trapz(y_data,x_data)        #unit=MJ
	workdone=area*1000                  #unit=kJ
	power=2*math.pi*rpm*(workdone/60)   #unit=kW
	return (workdone,power)

#Function to compute specific fuel consumption
def bsfccomp(fuel_per_stroke,power,rpm):
	fuel_per_sec=fuel_per_stroke*rpm*(0.5/60)   #unit=gm/sec
	fuel_per_hour=fuel_per_sec*3600             #unit=gm/hr
	bsfc=fuel_per_hour/power                    #g/kWhr
	return bsfc


#Asking user for filename
filename=input("Enter filename: ")
filename=filename+'.out'
try:
    f = open(filename)
    # Do something with the file
except IOError:
    print("File not recognized. Please provide a valid CONVERGE output file")
else:
	with open(filename, "r") as file:
		first_line = file.readline()
		if '# CONVERGE Release Build 2.3.29/' not in first_line:
			print('Please provide a valid CONVERGE output file')
		else:
			#Asking user to input desired column numbers
			x, y = input("Enter two values for columns: ").split()
			#Converting strings into integers
			x=int(x)
			y=int(y)
			#Initializing null vectors
			name=[]
			units=[]
			array_x=[]
			array_y=[]
			pressure=[]
			volume=[]

			#Running a loop through each line of data file to extract the respective columns
			for line in open('engine_data.out'):
				if '#          Crank' in line:
					name=line.split( )
				if '#          (DEG)' in line:
					units=line.split( )
				if '#' not in line:
					array_x.append(float(line.split()[x-1]))
					array_y.append(float(line.split()[y-1]))
					pressure.append(float(line.split()[1]))
					volume.append(float(line.split()[7]))

			plt.figure(1)
			plt.plot(array_x,array_y,linewidth=3)
			xlabel=name[x]+units[x]
			ylabel=name[y]+units[y]
			plt.xlabel(xlabel)
			plt.ylabel(ylabel)
			title='Plot of '+name[y]+' vs '+name[x]
			plt.title(title)
			plt.savefig(title)
			plt.show()

			plt.figure(2)
			plt.plot(volume,pressure,linewidth=3)
			xlabel=name[8]+units[8]
			ylabel=name[2]+units[2]
			plt.xlabel(xlabel)
			plt.ylabel(ylabel)
			plt.title('Plot of Pressure vs Volume')
			plt.savefig('p vs v')
			plt.show()
			rpm=1500

			area_PV,power=powerfunc(rpm,volume,pressure)
			bsfc=bsfccomp(20*1e-6,power,rpm)
			print('Area under the PV diagram: ',area_PV,'kJn')
			print('Power Output of the Engine: ',power,'kWn')
			print('Specific Fuel Consumption: ',bsfc,'g/kWhrn')

Explanation of code algorithm:
Initially the functions are defined for the computation of power output (`powerfunc`) and Specific Fuel Consumption (`text(bsfccomp)`). The inputs for the respective parameters are given and the outputs are printed. The filename is input by the user and checked whether it exists in the directory. If it exists, the file is opened and the column names, units, and desired column data are extracted. The extracted data is appended into the respective vectors. The desired plots are plotted and the pressure vs volume diagram is also plotted. The initially defiend function's outputs for the specific fuel consumption and power output are printed.