Performing regression-based methods on viscosity of nano-enhanced PCM - Using ANN and RSM

Abstract Evaluation of the use of linear and nonlinear regression-based methods in estimating the viscosity of MWCNT/liquid paraffin nanofluid was investigated in this study. At temperature range of 5–65 °C, the viscosity of samples containing MWCNT nanoparticles at 0.005–5 wt.% which is measured by a Brookfield apparatus, was first evaluated to determine the response to the shear rate. The decrease in viscosity due to the increase in shear rate indicated that the rheological behavior of the nanofluid was non-Newtonian and therefore, in addition to temperature and mass fraction, the shear rate should be considered as an effective input parameter. Linear regression was performed by response surface methodology (RSM) and it was observed that the R-square for the best polynomial was 0.988. The results of nonlinear regression also showed that the neural network consisting of 3 and 13 neurons in the input and hidden layers was able to estimate the viscosity of the nanofluid more accurately so that the R-square value was calculated to be 0.998

Navigating viscosity of ferrofluid using response surface methodology and artificial neural network

Abstract The main purpose of this study is to investigate the capabilities of artificial neural network (ANN) and response surface methodology (RSM) in estimating the viscosity of Fe3O4 nanofluid. Nanoparticles increase the resistance to motion and thus boost the viscosity. Initially, the rheological behavior of the base fluid and nanofluid was investigated and it was found that both fluids are not particularly sensitive to the shear rate, which indicates the Newtonian behavior. Input parameters of temperature and volume fraction and output parameter, nanofluid viscosity were introduced to both techniques to find the best correlation in which the viscosity can be predictable. Comparison of R-square in ANN (0.999) and RSM (0.996) techniques showed that both techniques can navigate the viscosity well. Also the margin of deviation (MOD) and mean square error (MSE) for ANN were 4.22% and 0.0000741 which were lower than the corresponding values in RSM one (MOD = 5.52%, MSE = 0.00027)

A state-of-the-art review of energy-efficient and renewable energy systems in higher education facilities

Amid escalating energy demands and growing environmental concerns, educational institutions are transforming into crucibles for enduring innovation. This comprehensive review summarizes the complex relationship between Energy Efficiency and Renewable Energy Systems (EERES) within the sphere of educational institutions. By instituting Energy Efficiency initiatives, organizations can curtail energy consumption, resulting in substantial cost savings and a diminished carbon footprint. Moreover, the integration of renewable energy technologies empowers the localized generation of electricity, ensuring a reliable and sustainable energy source. Noteworthy in this study is the novel linkage of energy usage indicators to the comfort levels experienced in university settings during both summer and winter. An exhaustive examination of consumption indicators, rooted in the diverse activities on college campuses, further enriches the investigation. Beyond technical intricacies, this study scrutinizes the economic viability, environmental advantages, and educational significance of these integrated systems. Embracing EERES not only aligns with the commitment of educational institutions to environmental stewardship but also establishes a paradigm for broader communities. These institutions aspire to exemplify sustainable practices, influencing larger societal behavior positively. Various factors, including the institution’s type, energy source, facility nature, building construction, internal activities, weather conditions, and user behavior, wield substantial influence over energy utilization. This study offers a nuanced exploration, shedding light not only on the technical dimensions but also on the broader economic, environmental, and educational implications of adopting EERES

Two-temperature dual-phase-lags theory in a thermoelastic solid half-space due to an inclined load

This article addresses the thermoelastic interaction due to inclined load on a homogeneous isotropic half-space in context of two-temperature generalized theory of thermoelasticity with dual-phase-lags. It is assumed that the inclined load is a linear combination of both normal and tangential loads. The governing equations are solved by using the normal mode analysis. The variations of the displacement, stress, conductive temperature, and thermodynamic temperature distributions with the horizontal distance have been shown graphically. Results of some earlier workers have also been deduced from the present investigation as special cases. Some comparisons are graphically presented to estimate the effects of the two-temperature parameter, the dual-phase-lags parameters and the inclination angle. It is noticed that there is a significant difference in the values of the studied fields for different value of the angle of inclination. The method presented here maybe applicable to a wide range of problems in thermodynamics and thermoelasticity

Darcy flow and heat transfer of nanoliquid within a porous annulus with incorporating magnetic terms

Current investigation was carried out to analyze the treatment of nanomaterial within a domain which experienced magnetic force. Outer rhombus wall is cold and the inner circle has uniform heat flux and due to these conditions, carrier fluid rotates counterclockwise. Darcy law was used for simulation and Joule heating was neglected in equations. Influences of parameters were discussed in plots and contours and CVFEM has been employed to reach such outputs. Rotational core becomes stronger with the rise of Ra while opposite results have been accomplished with the soar of Ha. In cases with higher values of shape factor, Nu has higher values and a similar trend is reported for Rd. Moreover, Nu experiences 30% reduction when Ha augments. This negative impact becomes more sensible when radiation terms are added in equations. Inclusion of nano powders has a favorable impact on Nu although it has a negative impact on temperature gradient

A detailed hydrothermal investigation of a helical micro double-tube heat exchanger for a wide range of helix pitch length

The present study was numerically inquired the heat transfer performance and fluid flow characteristic of a helical micro double-tube heat exchanger (HMDTHX) using the finite volume method. The tube length was considered to be constantly equal to 30 mm, and 12 different configurations were modeled by changing in turn number and pitch length (P) for Reynolds numbers of 50, 100, 150, and 200. The findings indicated that the heat transfer would enhance by applying any helix angle in the straight tube. However, it had an optimum point which varied by Reynolds number (Re). Rising Re caused overall heat transfer coefficient (OHTC), pressure drop, and pumping power augment for all cases. Increasing P in overall reduced OHTC, pressure drop, and pumping power which had different maximum points between P = 0.5 to 3. Maximum overall heat transfer coefficient (OHTC) enhancement was equal to 45% for Re = 200 and P = 2. Also, maximum effectiveness was 11.5% for P = 2 and Re = 200. Moreover, a 42% maximum increment was achieved for pressure drop, pumping power, and friction factor at Re = 200 and P = 2. Shear stress for Re = 100 to 200 showed that the values are almost the same for P = 0.5 and 1. Then by increasing P, the shear stress decreases. While, for Re = 50, a maximum is seen at P = 2. The temperature distribution was indicated that the maximum temperature of the straight tube and helical tube are the same, but the difference is in the average temperature, which was 3.2 K between straight and helical tubes. Finally, by investigating the velocity contour, it was determined that a secondary flow through the HMDTHX, affected by centrifugal force, was existed, enhancing the fluid flow turbulency and heat transfer rate

2000: Effect of tillage treatments on soil thermal conductivity for some Jordanian clay loam and loam soils

Abstract Soil thermal conductivity determines how a soil warms or cools with exchange of energy by conduction, convection, and radiation. The ability to monitor soil thermal conductivity is an important tool in managing the soil temperature regime to affect seed germination and crop growth. In this study, the temperature-by-time data was obtained using a single probe device to determine the soil thermal conductivity. The device was used in the ®eld in some Jordanian clay loam and loam soils to estimate their thermal conductivities under three different tillage treatments to a depth of 20 cm. Tillage treatments were: notillage, rotary tillage, and chisel tillage. For the same soil type, the results showed that rotary tillage decreased soil thermal conductivity more than chisel tillage, compared to no-tillage plots. in no-till treatments. The clay loam generally had lower thermal conductivity than loam in all similar tillage treatments. The thermal conductivity measured in this study for each tillage system, in each soil type, was compared with independent estimates based on standard procedures where soil properties are used to model thermal conductivity. The results of this study showed that thermal conductivity varied with soil texture and tillage treatment used and that differences between the modeled and measured thermal conductivities were very small.

Experimental and theoretical study of a vane pass frequency for a centrifugal pump

Centrifugal pumps are used for different applications that include pressure boosting, wastewater, water supply, heating and cooling distribution and other industrial processes. This paper presents theoretical and experimental investigations of mechanical vibrations of a centrifugal pump. The flow in this pump, which induces pressure pulsations and mechanical vibrations, have been monitored. Vibration measurements and data collection (overall vibrations levels and frequency spectrum) were extracted from the system. In addition, one of the methods used to study vibration amplitudes for this pump is forced response analysis. To study and analyze the pump system, the finite element analysis software (ANSYS) was applied. Depending on the analysis performed and investigations outcomes, the system natural frequency coincides with the vane-pass frequency (VPF) hazardously. To attenuate the system’s vibration, a vibration control element was used. The vibration levels were reduced by a factor of 2 for a tuned element as obtained from a forced harmonic response analysis of the pump system with absorber. It is shown that the inserted element allows the centrifugal pump to work in a safe operating range without any interference with its operation