Ciencias Exactas y Ciencias de la Salud
Permanent URI for this collectionhttps://hdl.handle.net/11285/551039
Pertenecen a esta colección Tesis y Trabajos de grado de las Maestrías correspondientes a las Escuelas de Ingeniería y Ciencias así como a Medicina y Ciencias de la Salud.
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- Numerical investigation on the heat transfer enhancement by the combination of wavy tape, dimples and nanofluids in a PTC receiver.(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2021-09-10) Cuevas Iturbe, Luis Donaldo; RIVERA SOLORIO, CARLOS IVAN; 121148; Rivera Solorio, Carlos Iván; tolmquevedo; Bretado de los Ríos, Mariana Soledad; Morales Menéndez, Rubén; School of Engineering and Sciences; Campus Monterrey; Gijón Rivera, Miguel ÁngelParabolic trough collector (PTC) is the most developed concentrating solar technology. It represents a viable way to substitute fossil fuels in the production of heat process, however higher thermo-hydraulic performance is needed to be more competitive. This study presents a numerical investigation of dimples, wavy tape and nanofluids (Al2O3, TiO2 and Al2O3-TiO2 dispersed in water at 4% concentration) in combination, in a PTC receiver. Fluent was used to solve the fluid dynamics and heat transfer characteristics inside the PTC receiver with the different heat transfer enhancement techniques for Reynolds numbers ranging from 1.48x104 to 1.77x105. The study showed that dimples with Al2O3/water nanofluid lead to a higher thermo-hydraulic performance evaluated with the Thermal Performance Index with values as high as 1.78. It was also proven that the highest thermal enhancement is obtained when the three heat transfer augmentation techniques are used in combination (wavy tape, dimples, and Al2O3/water nanofluid) with a heat transfer coefficient enhancement of 3.12 times that of a plain PTC receiver with no thermal enhancement. Nonetheless, the combination of techniques also come with a high cost of pressure drop increase from 8.52 to 12.59 compared to the plain PTC receiver. The combination of all the techniques proved more useful at low Reynolds numbers because the flow is not as turbulent. As Reynolds number increases, the thermal increase is not proportional to the mean pressure drop increase, then leading poor performances at high Reynolds numbers. On the other hand, wavy tape with nanofluids proved to have better thermal performances at high Reynolds numbers. The use of nanofluids always leads to the higher thermal performance values. Regarding the different nanofluids, the difference among them is non-significant compared to each other in terms of mean pressure drop, however in terms of heat transfer coefficient improvement, there is about 1.34% difference between the highest thermal performance nanofluids (Al2O3, and Al2O3-TiO2) and TiO2/water nanofluid.
- Numerical Analysis of Heat and Mass Transfer in Emerging Technologies of Cooling Systems(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2020-06-15) Mitz Hernández, Enrique; MITZ HERNANDEZ, ENRIQUE; 881783; Rivera Solorio, Carlos Iván; ilquio, emipsanchez; Huertas Cardozo, José Ignacio; School of Engineering and Sciences; Campus Monterrey; Gijón Rivera, Miguel AngelWe numerically analyze two distinct technologies for air cooling systems: (1) Dew-Point Evaporative Cooling (DPEC) Systems, and (2) Nanofluids in Helical Coils Heat Exchangers (HCHE). For the first technology, we developed a 1D model with thermophysical properties dependent on the temperature, humidity ratio and atmospheric pressure. The model was evaluated under different conditions in a parametric analysis. Then, a regression maintaining the same atmospheric pressure and channel length was found for the DPEC model. The regression shows a good fit with modeled data, having a RMSE of 1.4 and R2adj of 93%. Also, the model was evaluated in 4 climates (Very arid, arid, warm, and mild). On the other hand, the Nanofluids in HCHE model was implemented in the commercial software Fluent. The optimal mesh consists of 3.529 Million of elements using a structured mesh. The model implemented was set in a turbulent regime, with thermophysical properties dependent on temperature and constant wall temperature and uniforms inlet velocity and temperature. The thermophysical properties for the nanofluids were set from thermophysical properties dependent on the temperature of the base fluid and constant thermophysical properties of the nanoparticle. Then, a case analysis varying the geometry, Dean number, nanofluid (base fluid and nanoparticle) and nanoparticle volume concentration was developed. Finally, from the data modeled we found a correlation for Nusselt number of the Water / Alumina nanofluid.