Study And Development Of Corrugated Tubes

As a kind of heat-transfer equipment, heat exchanges have been widely used in refinery, chemical, light industry, drugs manufacture and urban's central heating system, etc. They are the essential equipment in the industrial production. In recent years, many scholars have devoted their efforts to the research and development of high efficient heat exchangers with the stress on the heat transfer enhancement behaviors.Corrugated tube heat exchanger is one of new kind shell-and-tube heat exchanger which has good heat transfer, anti-scaling and self-compensation abilities. In order to study the axial stiffness of the corrugated heat exchange tubes, two double-pipe heat exchangers respectively using corrugated tube and smooth tube were designed and the axial stresses at the outer tubes under the thermal loadings were evaluated both numerically and experimentally. It was found that owing to the larger deformation compensation ability, the axial stress at the outer tube of the corrugated double-pipe heat exchanger is about 40% of that for smooth double-pipe heat exchanger, meaning that the corrugated double-pipe heat exchanger is more able to undertake to thermalloading. Finally, the stiffness weakening factor k_f was proved in the purpose of facilitating the engineering application of the corrugated heat exchange tubes.Numerical simulations were carried out for the fluid flow in four types of corrugated tubes including the arc-tangent corrugated tube developed by Prof. Qian Caifu of the Beijing University of Chemical Technology. Convection heat transfer coefficients and pressure drop were analyzed and compared between different corrugated tubes and plain tube. Results show that all corrugated tubes give much higher convection heat transfer coefficients but the sinusoidal and arc-tangent corrugated tubes are the best compared with the other types of corrugated tubes in terms of the heat transfer coefficient per unit pressure drop.