The third case study is the TTHE studied by Batmaz and Sandeep . The apparatus considered is a heat exchanger (assumed to be horizontal) with corrugated walls and four linear sections, each 5.65 m long. See Table for other geometric characteristics. In the inner annular section flows water with a back pressure valve at the outlet set to 4.08 atm to prevent boiling. A 70% water/30%