Mapping of Flow Visualization and Heat Transfer Analysis Over Roughened Plate Inside Rectangular Duct

  • Anup KumarEmail author
  • Apurba Layek
Conference paper
Part of the Advances in Intelligent Systems and Computing book series (AISC, volume 755)


In recent decades, liquid crystals thermography (LCT) technique which is optical and inexpensive technique for visualizing surface temperatures distribution and measuring heat transfer coefficients. The optical technique is build with the help of thermo-chromic liquid crystals enforced to the test surface. The main objective of this study is to visualize temperature fields through image processing for certain set of working parameters and to study of heat transfer characteristics with turbulators mounted over flat plate in a rectangular channel. The working geometric parameter for the roughened rectangular air duct are angle of attack of fluid flow (α) with the range of 30°–90°, relative pitch ratio (P/e) with range of 7–9, relative twist ratio (Y/e) with of range 3–5 and Reynolds number (Re) with the range of 14000–21000. Predictions of Nusselt number with roughened surface is compared with the smooth duct with same condition.


Solar air heater Heat transfer Liquid crystal thermography Image processing 



Length of the duct, m


Width of the duct, m


Depth of the duct, m


Relative pitch ratio (dimensionless)


Relative twist ratio (dimensionless)


Angle of attack (degrees)


Hue (dimensionless)


Mean temperature of air (°C)


Temperature of LCT sheet/absorber plate (°C)


Hydraulic diameter (m)


Thermal conductivity of air (W/m°C)


Wind velocity of air (m/sec)


Kinematic viscosity (m2/s)


Convective heat transfer coefficient (W/m2°C)


Convective heat flux (W)


Nusselt number (dimensionless)


Reynolds number (dimensionless)



The authors gratefully acknowledge the financial support of the Science and Engineering Research Board (SERB), Department of Science and Technology (DST), Govt. of India for initiating this research activity in Mechanical Engineering Department at National Institute of Technology Durgapur, India—Reference SERB-DST Grant: SB/EMEQ-314/2013; dated: 08/07/2013.


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© Springer Nature Singapore Pte Ltd. 2019

Authors and Affiliations

  1. 1.Department of Mechanical EngineeringNational Institute of Technology DurgapurDurgapurIndia

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