Improving the performance of heat exchanger surface by industrial roughness

One popular heat transfer augmentation technique involves the use of rough surfaces of different configurations. The rough surface aims to promote surface turbulence that is intended mainly to increase the heat transfer coefficient and surface area. It was reported that non-flat surfaces have free convection coefficients that arrive to 50% to 100% more than those of flat surfaces. The goal of this study aims mainly to examine heat transfer enhancement from a surface with same industrial roughness created by a special tool (roughness surfaces) with different shapes under convection heat transfer compared to equivalent smooth surfaces without deformations. The results show there is no need to apply the different roughness configurations in two mutually perpendicular directions. It's enough to cause it only in one plane. And we have got the same win in surface area. The results show also the rectangular profiles of roughness give the best result.

Analyzing of Convection Heat Transfer in Absorber Tube of Direct Steam Generation Parabolic Trough Collector (DSG-PTC)

Direct steam generation in parabolic trough collector (DSGPTC) has had a great importance because of its thermoeconomic advantages and many researches have be done in this field. Due to that reason this paper studies the convection heat transfer from absorber tube of a PTC to all phases of water (liquid water, wet steam and dry steam) along the whole distance of fixed length of a DSG-PTC generates a high temperature superheated steam (561 °C). All heat transfer operations in PTC has been modelled and then the convection' components which are; fluid temperature, tube wall-fluid temperatures difference and heat transfer coefficient have been analyzed in details at different operation conditions such as inlet fluid pressure, direct solar beam and mass flow.

Experimental Study for Determination the temperature distribution of the roughness surfaces under natural convection

This study aims mainly to determine the temperature distribution heat transfer enhancement under natural convection experimental, from three surfaces with industrial roughness created by a special machine (roughness surfaces) with triangular, trapezoidal, spherical configuration compared to equivalent smooth surface. With cross-sectional area.