Добавьте этот код ниже в постпроцессоре Bean Shell
a = vars.get("PARAM_1"); // PARAM_1 is parameter/correlation variable
b = vars.get("PARAM_2"); // PARAM_2 is parameter/correlation variable
f = new FileOutputStream("FILEPATH/filename.csv", true);
p = new PrintStream(f);
this.interpreter.setOut(p);
print(a +","+ b);
f.close();