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

Department of Chemical Engineering

Indian Institute of T echnology Bombay

Sachin kumar Jitesh Phulwani Baljeet Singh

Aim of the experiment

• T
• determine the overall heat transfer coefficient making use
• f 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

1 ℎ𝑗𝐵𝑗 ∆𝑦 𝐿𝐵𝑚𝑛 1 ℎ𝑝𝐵𝑝

1 𝑉𝑗𝐵𝑗 = 1 ℎ𝑗𝐵𝑗 + ∆𝑦 𝐿𝐵𝑚𝑛 + 1 ℎ𝑝𝐵𝑝 1 𝑉𝑗 = 1 ℎ𝑗 + ∆𝑦𝐵𝑗 𝐿𝐵𝑚𝑛 + 𝐵𝑗 ℎ𝑝𝐵𝑝

• Dittus-boelter equation

𝑂𝑣 = 0.0023(𝑆𝑓0.8)(𝑄𝑠0.3) 𝑂𝑣=const*(𝑤𝑓𝑚𝑝𝑑𝑗𝑢𝑧0.8)

• Final equation

1 𝑉𝑗 =const1 1 𝑣0.8 + 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

• utlet 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 Obs Hot fluid flow rate (lph) Hot fluid temperature (0C) Cold fluid temperature (0C) Inlet (T1) Outlet (T2) Inlet (t1) Outlet(t2)) 1 2 3 4 5 6

Thank you