using response surface methodology (rsm) to evaluate the drag reduction by polyacrylamide, experimental and statistical investigation

In the present study, the effect of polyacrylamide (pam) addition as a drag reducing agent on the hydraulic performance of water flow inside horizontal smooth circular pipe was investigated experimentally and statistically. several experiments were performed under various operating circumstances such as fluid flow rates (q) at the 6,8,10 l/min, concentrations (c) of 10,100, 200 ppm, and temperatures (t) of 30, 40, and 50 ◦c. the main aim of this study was to establish the correlation between darcy friction factor (f) and c, q and t using response surface methodology (rsm). different models were evaluated based on a series of quality indicators and charts. some of the indicators that were investigated in this study include standard deviation (std. dev.), coefficient of determination (r2) and coefficient of variation (c.v). after checking the quality indicators and charts for different models, the quadratic model was selected as the optimal model. the values of std. dev, r2 and c.v for the quadratic model were 0.0011, 0.9856, and 3.18%, respectively. the most optimum f is 0.022. at a temperature of 30 °c, this condition was achieved in samples at c=182.111 ppm and q = 10 l/min.