Development of the New Comprehensive Performance Evaluation Equipment for Enhanced Convective Heat Transfer Techniques
Based on the new performance evaluation criterion system (PECS) for enhanced convective heat transfer techniques, an evaluation equipment of enhanced heat exchange tube was developed. The equipment structure and functions, parameters measurement and control of auxiliary system were introduced in detail. The monitoring and control software was programmed with the Delphi 7.0, and be used to realize the data acquisition and processing, database operation and management, and many other functions. A kind of new type enhanced heat exchange tube was tested. The experience result shows that apparatus is feasible to evaluate the performance of enhanced convection techniques.
The Analysis of the Effect of Fouling on the Performance of the Fill Layer
Based on that the film filling was simplified to the flat plate model, the heat and mass transfer of the filling zone with fouling in cooling tower were analyzed. The effect of fouling on the performance of filler was analyzed according to the dirt growth model. The work done in this paper can simply forecast changes in cooling tower performance caused by the filler fouling. It will lay a theoretical foundation for accurately calculating the performance coefficient of filler. And it is helpful to solving the problem of no the ripe empirical formula of filler performance with fouling for engineering applications.
Electric stress and heat transfer
Apparent contradictions in published reports of the effect of electric stress on heat transfer in fluids have been resolved by small-scale experiments and by reanalysis of available data. The effect of deliberately mixed unidirectional and alternating stress has been investigated for the first time. While alternating stress increases heat transfer in its presence, purely unidirectional stress inhibits it, while "mixed" stress may have either effect according to the magnitude of its components.