Flow HT208 People associated with the expt. Instructor Prof. - PowerPoint PPT Presentation

Heat Transfer in Laminar Flow HT208

People associated with the expt. • Instructor • Prof. Jayesh Bellare • Teaching Assistants • Satpute Kushal Dadasaheb • Sudip Kumar Das • Praveen Nayak • Laboratory Staff Member • Mr. S. V. Deshpande

Objective For laminar flow heat transfer • Determination of the overall heat transfer coefficient using logarithmic mean temperature difference • Calculation for the individual film heat transfer coefficient

Principle

Background Theory With respect to the inside area Sieder-Tate equation Nu = 1.86 x (Re) 1/3 (Pr) 1/3 h = const. x u 1/3 1 1 𝑣 1/3 + Constant 2 = Constant 1 x 𝑉 𝑗

Set up Heat exchanger Flow regulator Rotameter Calibrated cylinder Pumps Heater

Experimental Procedure 1. Start up circulating pumps for both hot and cold fluid 2. Switch on the heater for heating up the hot fluid 3. Steady state reached:  Note hot fluid and cold fluid inlet and outlet temperature  Measure volumetric flow rate of hot fluid (laminar flow regime) 4. Change volumetric flow rate of hot fluid keeping other parameter unchanged 5. Repeate step no. 3

Data collection • From experiment • Cold fluid volumetric flow rate (fixed) • Cold fluid inlet and outlet temperature • Hot fluid volumetric flow rate (manipulated variable) • Hot fluid inlet and outlet temperature • From literature • Density of cold fluid at 30 O C • Density, viscosity, thermal conductivity and heat capacity of hot fluid at 65 O C • Supplied • Dimensions of heat exchanger, tubes

Calculation Q = V x ρ x Cp x (T 1 -T 2 ) 1/U 𝑈 1 − 𝑢 1 − (𝑈 2 − 𝑢 2 ) LMTD = * 𝑈 1 − 𝑢 1 /(𝑈 2 − 𝑢 2 )+ ln⁡ 𝑅 U = 𝐵Δ𝑈 𝑚𝑜 1/u 1/3 Wilson Plot for Laminar flow heat transfer

Safety issue • Careful during volumetric flow rate measurement of hot fluid

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