Thermal behavior of fluid within pipes based on discriminated dimensional analysis. An improved approach to universal curves. (25th February 2018) - Seco-Nicolás, Manuel
Graphical abstract: Highlights: Discriminated dimensional analysis approaches a universal solution of Graetz Problem. A universal characteristic length abacus is offered; further pipe length is useless. Universal abacuses of temperature along the pipe is included. Universal abacuses of local and cumulated heat along the pipe is presented. Use of abacuses for design purposes is described. Abstract: A new approach to the heat transmission problem concerning a fully developed laminar flux inside a pipe subject to an abrupt change of temperature in non-reactive conditions is presented. By means of dimensional discriminated analysis, representative dimensionless groups of 2D governing equations and boundary conditions of the problem are managed in order to find a set of dimensionless groups which describe the system's behavior. The characteristic length of the system, which plays a key role in the formulation, as well as the heat transfer and thermal distribution, are obtained numerically for the range of values of solar thermal flat-plate collectors using the network simulation method. The set of universal abacuses of temperature and heat based on the new dimensionless groups can be used in the design of industrial thermal devices and facilities.