Category Archive Projects

BySTEER EESC

Experimental study of falling film absorption process of ammonia-water mixture

Main researcher:

Prof. José R. Simões-Moreira

Description:

We will realize a parametric study of falling film absorption process of ammonia-water mixture. Heat and mass transfer coefficients for a broad range of operational conditions will be experimentally evaluated. Initially, theoretical aspects related to the absorber will be studied through a simple one-dimensional modeling of the falling film absorption process in a refrigeration cycle with ammonia-water as working fluid, in order to establish optimal operating conditions. Then, the absorber and the refrigeration cycle will be experimentally analyzed, enabling a validation of the theoretical model. Finally, heat and mass transfer coefficients, and the coefficient of performance will be calculated for various experimental conditions, creating a solid and broad database.

BySTEER EESC

Development of instrumentation and control techniques for phase-change heat transfer applied to passive pulsed circuits

Main researcher:

Prof. Cristiano Bigonha Tibiriçá

Description:

Our goal is to develop instrumentation techniques applied to an experimental setup for investigating phase-change heat transfer in passive pulsed circuits. Fundamental aspects of liquid/vapor interfacial heat transfer in pulsed flows like the thickness of liquid film, heat transfer coefficient and void fraction will be evaluated, respectively, through laser focus displacement, infrared temperature measurements, and volumetric reconstruction based on image processing. In addition, these circuits will be actively controlled by micro-actuators, in order to keep optima operational conditions.

BySTEER EESC

Development of high-performance microchannels-based irradiation absorbers containing micro- and nanostructured surfaces applied to solar receptors

Main researchers:

Prof. Gherhardt Ribatski

Prof. José Alexandre Diniz

Prof. Luben Cabezas-Gómez

Collaborators:

Prof. Luís Alberto Barêa

Prof. Giuseppe Cirino

Prof. Newton Frateschi

Prof. Stanislav Mochkalev

Description:

The main objective is to develop solar irradiation absorbers that efficiently convert the absorbed energy into thermal energy through flow boiling in microchannels. In order to achieve the proposed objective, a detailed study of the literature concerning flow boiling in multi-microchannels heat sinks will be carried out, such that some design guidelines for channels distribution and surface engineering for optimum heat sinks can be defined, based in previous investigations; fundamental aspects of confined flow boiling will be studied using rapid infrared imaging; a computational tool based on Lattice-Boltzmann method will be developed, such that bubble growth and detachment in confined and free conditions can be simulated and later extended to flow boiling in microchannels with distinct geometries; the best performing proposed geometries will be fabricated with micro- and nanofabrication techniques, then will be characterized  based on their heat transfer capacity, critical heat flux, pressure drop, and thermal stability.