Question

​​​​​​​Please answer clearly and neatly so I can read your work. I will give a good rating! Thank you (:

Consider a concentric tube heat exchanger with hot and cold water inlet temperatures of 202 and 35°C respectively. The flow rates of the hot and cold fluids are 42 and 84 kg/h, respectively. Assume the overall heat transfer coefficient is 178 W/m2k. cc = 4186 J/kgk, ch = 4302 J/kgK What is the maximum heat transfer rate that could be achieved for the prescribed inlet conditions? Amax = W If the exchanger is operated in counterflow with a heat transfer area of 0.33 m2. Determine the outlet fluid temperature. T6,0 = °C

Answer 1

Griveni Concentric Tube Heat exchanger, Lature Inlet Conditions 1) Inlet tempereature of - hot water (Th); = 202°C li) Inlet temperature of cold water (T); - 35°C Mass flow rates of hot - fluid (m) at 42 kg/ba Mass flow rate of - cold fluid (m) c= 84 kg/h. Overall heat transfer Coefficient (0) = 178 W/m Specific heats: (c = 4186 I lkg k

- Ch=4302J 1 kg k Now i) qmax= ? . Watts ( Maximum heat transfer rate) for Max heat transfer rate any heat exchanger is &max= Cmin (AT) max muy (Atbrev = () - (-);) .: max = Comin (Th); - (2) rmax where in Minimum value тух )

But . l hour= 3600sec hour mi x 6 = 84 x 4186 el 5.97.64 ( care ) = 97064 sec But Sec mix (63.97:64 cm) = 94.64

Similarly, min = 42 1 kg 360o mixch= 42 x 4302 1 3 600 imum mixin = 5010 W Cmina Mimimum of [a4-6-1, 5o-in] (min = 50.19 w Imax= ( min (Thi-T(1) = 50-14|(20121) - ) max - 20+JYR = 50-19 com (354209)) = 5019 (202- 35) (11)• c = (57)* (Temperature dift. oc) come in kelvin &

.50-19(164) = 838167 W - Maximum heat transfer 19 max) = 83 81-74 *) Now when exchanger operated in counterflow with Areal A)= 0-3 3m? Coutlet fluid temperature) = ? for cold body . Tc,o=? Co We have : NTUS UA set) - (min LMTO lov Q = UA (LMTD) (standard formula)
These are the formula for calculating second sum that is cold fluid outlet temperature.But with given it is not possible to find it.So please post if any data is missing will solve it and again post it.