Banca de QUALIFICAÇÃO: RAFAEL MÓDOLO DIAS DUARTE

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : RAFAEL MÓDOLO DIAS DUARTE
DATE: 13/03/2024
TIME: 10:00
LOCAL: On line
TITLE:

A DETAILED INVESTIGATION OF HEAT TRANSFER ENHANCEMENT, FLOW PATTERNS AND HEAT TRANSFER CHARACTERISTICS OF LOUVERED-WINGLET VORTEX GENERATORS MOUNTED ON SOLAR AIR HEATER CHANNELS

PAGES: 74
BIG AREA: Engenharias
AREA: Engenharia Mecânica
SUBÁREA: Engenharia Térmica
SPECIALTY: Aproveitamento da Energia
SUMMARY:

The solar air heater (SAH) equipped with special modified surface geometries is one of the existing technologies capable of converting the solar energy into thermal energy with low associated pressure drop, and it has been used as heat source in a wide range of thermal applications which demand lower operating temperatures (about 30ºC to 80ºC). In the present research, the use of louvered longitudinal vortex generators (LVGs) as a passive heat transfer enhancement technique is proposed to numerically investigate the effect the opened louvers have on the SAH thermo-hydraulic performance, using as a base of comparison the performance with full LVGs, for the Reynolds numbers of 5000 and 20000, two different types of LVGs — delta winglets and rectangular winglets — aspect ratios of 2 and 6, angles of attack of 30° and 45°, ratios between louver area and LVG area of 0.25 and 0.44, louver flap angles of 10°, 40°, and 60°, and two louver opening directions — pointing to the adiabatic plate or to the absorber plate, both downstream the main flow. The numerical simulations showed that louvered winglets mounted in common-flow-down configurations are thermo-hydraulically more efficient than the respective non-louvered ones, while rectangular winglets, and higher values of louver flap angle, aspect ratio, and ratio between louver area and LVG area promoted a better performance of the channel. The effect of the louver on the performance of the SAH channel is more pronounced with rectangular winglet than delta winglet. Moreover, the LVGs with louvers towards the adiabatic plate introduce less pressure loss to the SAH than the ones with louvers towards the absorber plate, achieving maximum thermal enhancement factors, respectively, of 3.418 and 3.012. With respect to heat transfer characteristics and flow patterns observed on louvered winglets, a new vortex structure generated by the louver openings is identified, which is responsible to enhance the hot and cold flow mixing. Finally, the louver presents similar effect on thermo-hydraulic performance for both Reynolds numbers.

COMMITTEE MEMBERS:
Presidente - Interno ao Programa - 2312727 - DANIEL JONAS DEZAN
Membro Titular - Examinador(a) Interno ao Programa - 1600874 - MARCELO MODESTO DA SILVA
Membro Titular - Examinador(a) Externo ao Programa - 2418500 - LORETO PIZZUTI
Membro Suplente - Examinador(a) Interno ao Programa - 1985515 - ANTONIO GARRIDO GALLEGO