Evaporation is one of the most used phenomena in industrial process. It wasevident from the literature review that the problem of film evaporation outsideborizontal grooved tube still needs more investigation. Therefore the present work is concerned with the study of water film evaporation heat transfer outside a horizontal grooved tube. The problem is tackled theoreticall y and experimentally. The theoretical work introduces a simple model for calculating heat transfer coefficient outside a horizontal grooved tube. For this purpose, ahelically U-grooved tube is proposed to investigate the effect of the mainparameters such as mass flow rate per unit length, temperature difference andand photoelesticity methods were used to investigate.,.tnti’oned variables on the mechanical behaviour ofeach other showing a reasonableand recommendations concerning thertance of usmg semells, its rigidity, location under differentCir4N1llstance hich may be of great use for designers were arised.