Heat Transfer In Turbulent Flow Lab- CL 232 Expt. No. HT-209 - PowerPoint PPT Presentation

Heat Transfer In Turbulent Flow Lab- CL 232 Expt. No. HT-209 Sachin kumar Jitesh Phulwani Baljeet Singh Department of Chemical Engineering Indian Institute of T echnology Bombay

Aim of the experiment • T o determine the overall heat transfer coefficient making use of logarithmic mean temperature difference (LMTD). • To determine the individual film heat transfer coefficients and verify Dittus-Boelter equation for turbulent flow heat transfer.

Theory • Overall resistance = sum of resistance in series 𝑉 𝑗 𝐵 𝑗 = 1 1 ℎ 𝑗 𝐵 𝑗 + ∆𝑦 1 𝐿𝐵 𝑚𝑛 + ℎ 𝑝 𝐵 𝑝 𝑉 𝑗 = 1 1 ℎ 𝑗 + ∆𝑦𝐵 𝑗 𝐿𝐵 𝑚𝑛 + 𝐵 𝑗 ℎ 𝑝 𝐵 𝑝 • Dittus-boelter equation 1 ∆𝑦 1 𝑂𝑣 = 0.0023 ( 𝑆𝑓 0.8 )( 𝑄𝑠 0.3 ) ℎ 𝑗 𝐵 𝑗 𝐿𝐵 𝑚𝑛 ℎ 𝑝 𝐵 𝑝 𝑂𝑣 =const*( 𝑤𝑓𝑚𝑝𝑑𝑗𝑢𝑧 0.8 ) • Final equation 1 1 𝑉 𝑗 = const 1 𝑣 0.8 + const2

Experimental setup Flow meter(Rota-meter) Digital display Double pipe heat exchanger

Experimental procedure 1) Switch on the temperature indicator and controller. Check the set point of the controller. The set point will be around 65 to 70 ° C. 2) Start the hot fluid circulation pump. Initially keep the flow rate at low speed by a regulator. Note down the temp difference between inlet and outlet temperatures, which gives zero error. After noting down the zero error, switch on the heater. 3) Keep the cold fluid flow rate at 240lph. Keep this flow rate constant through out the experiment. 4) Adjust the hot fluid flow rate by regulator (the minimum flow rate of hot fluid should be at least 40 cc/s, or 144 lph to maintain Reynold's number above 10000 in the heat exchanger). 5) Note down the inlet and outlet temperatures of hot and cold Fluid after steady state is reached. 6) Repeat step4 & 5 for at least 6 different flow rates of hot fluid.

Data to be collected • Dimensions of inner and outer tube of the double pipe heat exchanger. • Physical properties of hot fluid (mono ethylene glycol, MEG) at the set temperature (65 ° C). No of Hot fluid flow Hot fluid temperature Cold fluid temperature rate (lph) Obs ( 0 C) ( 0 C) Inlet (T 1 ) Outlet (T 2 ) Inlet (t 1 ) Outlet(t2) ) 1 2 3 4 5 6

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