Example #1 Situation: Light lubricating oil(cp=2090 J/kg-K)is cooled with water in a small heat exchanger Oil flow=0.5 kg/s. inlet T=375K Water flow=0. 2 kg/s, inlet T=280K Part 1 If desired outlet temperature of the oil is 350 K and you know the estimated overall heat transfer coefficient U=250 W/m2-K. from manufacturer 's data for this type of hX Find: Required heat transfer area for a parallel flow hX and compare to the area needed for a counter flow hX 350K Solution Method? =375K waterout LMTD water, Ii 280K Heat Transfer Su Yongkang School of Mechanical EngineeringHeat Transfer Su Yongkang School of Mechanical Engineering # 11 Example #1 Situation: • Light lubricating oil (cp=2090 J/kg-K) is cooled with water in a small heat exchanger. • Oil flow = 0.5 kg/s, inlet T = 375 K • Water flow = 0.2 kg/s, inlet T = 280 K Part 1: • If desired outlet temperature of the oil is 350 K, and you know the estimated overall heat transfer coefficient, U = 250 W/m²-K, from manufacturer’s data for this type of HX • Find: Required heat transfer area for a parallel flow HX and compare to the area needed for a counter flow HX. Toil,in = 375K Toil,in = 350K Twater,in = 280K ? Twater,out = Solution Method? • • • LMTD