In this paper. the challenge is to increasing of the heat exchanger performance by placing different size balls inside the tubes. the development of previous studies to enhance relatively bad case of heat transfer where the inserting (a large ball and then a small ball) to collide the water molecules in the ball and generate turbulent flow (Reynolds number range from 50. 000 to 350. https://www.pomyslnaszycie.com/life-is-better-with-my-boys-womens-graphic-tee-ice-blue-online-now/