Calculations related to heat exchangers

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Steps for the design calculation of heat exchangers: 1. Natural convection heat transfer outside the tubes; 2. Forced convection heat transfer outside the tubes; 3. Condensation heat transfer outside the tubes. Given: the flow rate of the oil-water mixture in the tube side, G (m3/d); the length of the tubes in the tube side, L (m); the outer diameter of the tubes, do (m); the inner diameter of the tubes, di (m); the temperature of the hot water, t °C; the inlet temperature of the oil-water mixture, t1’ °C; and the outlet temperature of the oil-water mixture, t2” °C. 1. Natural convection heat transfer outside the pipe 1.1 Setting of wall temperature: First, the wall temperature is determined; generally, it is taken as the average of the temperature of the hot water and the exit temperature of the oil-water mixture, denoted as tw ℃. The temperature of the hot water is t ℃, while the inlet temperature of the oil-water mixture is ℃, and its exit temperature is ℃. 1.2 Calculation of qualitative temperature and physical property parameters: When the fluid outside the pipe is water, its qualitative temperature is °C; when it is an oil-water mixture, the qualitative temperature is ℃