Jorge Duarte

Parametric study of cascade and multi-stage vapor compressor refrigeration systems using a Matlab guide

This paper shows the application of a software tool to promote the significant learning in refrigeration cycles in undergraduate engineering students through case studies. To solve the case studies the tool calculates in MATLAB® the thermodynamic states and energy balances of the simple vapor refrigeration cycle, the cascade, multi-stage, and absorption refrigeration cycle. In the case of a simple refrigeration system, a proportional behavior between the COP and the compressors work was obtained as a function of the outlet temperature of the evaporator for compressor efficiencies of 100%, 80%, and 60%. In the case of the cascade refrigeration system, the behavior of both the energy consumed by the compressor and the thermal efficiency of the cycle is explained by the pressure at the inlet of the high compressor. In the multi-stage refrigeration cycle, the variation in the pressure of the flash chamber and the compressor efficiency did not affect the vapor fraction. Finally, the case studies obtained through the program facilitate the understanding of thermodynamic phenomena in refrigeration systems, which normally in a traditional classroom would require time and educational resources for their learning. 1262 Guillermo E. Valencia et al.

Implementation of a fuel measurement system based on the gravimetric principle for applications in engine test bench

This paper documents the implementation process of a fuel measurement system based on the gravimetric principle for applications in Engine Test Bench. To do this, the design of the measurement hardware consists of a gravimetric scale with serial output, feed pump, and a valve; which interact with each other thanks to the programming developed in the Arduino UNO® environment, it is possible to guarantee protection against possible disturbances that may affect the data measured by the scale by means of an acrylic structure. For the visualization and interaction with the information collected by the meter, an executable application 3782 Jorge Duarte et al. is made using the LabView TM computational tool. Finally, a series of runs are carried out to guarantee compatibility with the existing testbench in the laboratory and to demonstrate the functionality of the system.

Effect of the insulation and the material of the inclined sheet on the drying of anhydrous lactose in a continuous vertical fluid bed dryer

The present study shows the effect of the diffusivity of the material of the internal inclined sheets on the drying of granular anhydrous lactose with an average particle diameter of 1.68 mm in a continuous powder dryer with adjustable inclined sheets. It was reduced the heat losses in the equipment with an insulator, maintaining the air inlet temperature in 100oC. To increase the solid-air contact, perforated plates were designed in a square arrangement in line. They were adapted inside the column with an inclination angle of 60o. It was found that the diffusivity of the material, the insulation, and their interaction have significative effects on the drying obtaining a statistical p-values lower than 0.05. The heat losses in the equipment were reduced in 13%.

Bibliometric and visualization analysis of sliding mode control research

Sliding mode control (SMC) is a nonlinear control method that alters the dynamics of a nonlinear system by application of a discontinuous control signal that forces the system to slide along a cross-section of the systems normal behavior. The growth and development of research productivity concerning sliding mode control in terms of publication output as reflected in the citation index of Web of Science (WoS) are analyzed for the period of 2001-2016 using HistCiteTM to know global publication share, rank, growth rate, h-index, output of top journals and highfrequency words in this field. With the help of HistCite software, the chronological citation chart is demonstrated to understand the basic situation and summarize the research status in the field of SMC.

Application of software packages on the parametric study of serial-driven planar manipulators

In this work, the kinetic and kinematic variables of serial-driven planar manipulators (also known as RR planar manipulators) were studied to achieve optimization in its performance through a parametric analysis. To do so, the equations that define the behavior of these mechanisms were programmed using the Octave software package, and some variations were made in input parameters, such as torque and forces, to study their influence on the kinetic parameters of the mechanism; to validate the obtained results, these were compared with the analytical solution, to guarantee the prediction capacity of the simulations. The results obtained by using the simulation package shared the same behavior as the results obtained through the application of the theoretical model, with a little deviation from the theoretical results (less than 3%). Besides that, the program code allowed to obtain results to a higher speed than the solution of theoretical equations (harder to solve at hand) with the same accuracy, which is an important parameter when optimization processes are required. 3640 Jorge Duarte et al.

Study of the influence of emissivity on the thermal performance of vertical unglazed transpired solar collector

In this work, the influence of the emissivity of a solar collector on its thermal performance was studied, to evaluate the effect of radiative heat losses on-air preheating appliances. To do so, the equations that define the efficiency of the unglazed solar collector were programmed into a commercial software package (such as MATLAB®, where the emissivity of the collector surface was varied, to study its response when a radiation boundary condition is changed; to validate the obtained results, a comparison with the theoretical results was done to verify the prediction capacity of the programming code. As the results obtained through the code shared the same behavior of the theoretical ones (though a little deviation), it was verified the capabilities of the program to accurately predict the collector efficiency with a higher speed, and at the same time, it allowed to establish that the increase in the emissivity generates a reduction in the thermal efficiency of approximately 20%, which makes it an important factor to control through the design and construction of solar collectors. 3656 Jorge Duarte et al.

Application of thermodynamical simulation in the economic evaluation of cogeneration and trigeneration systems

In this work, the application of simulation software as a tool in economic evaluation in cogeneration and trigeneration systems was studied. To do so, a simulation model was developed using a thermodynamical software, coupled with an economic evaluation add-on, to be validated using the results given by a theoretical model previously defined (and verified) in previous works. Variations were done in certain economic parameters of the model, in order to evaluate the behavior of a said system through the application of the theoretical model and simulation; The results allowed to conclude that the simulation model is able to accurately predict the theoretical results, with an error margin lower than 5%. Besides that, it was verified that the evaluated parameters, the electricity generation and chilling capacity, have a great influence over the cost of the trigeneration system, as these are the parameters that affect directly the energetic performance, and therefore have a great incidence in economic feasibility studies for the implementation of these strategies. 3326 Jorge Duarte et al.

Comparative study of the use of numerical methods in the solution of dynamic mechanical systems

In the present work, a comparative study of three numerical methods used in the solution of differential equations (Euler, Runge-Kutta and Verlet) was carried out, in order to evaluate the accuracy offered by each of these in the solution of dynamic systems, in addition to other characteristics, particularly the speed of convergence shown for each model, which relates directly with the computational load required for their operation. The methods used for the investigation were compiled in the free computational package Octave, which in turn is a tool with similar characteristics over its paid counterpart (MATLAB®), and applied over a fairly simple dynamic system, which comprises a physical pendulum. The results show that the classic methods (Euler and Runge-Kutta), were able to predict the response of the system accurately, but at a low speed of calculation, while Verlet’s integration method allowed to obtain convergence using a higher time step which implies a faster operation and a better accuracy than the other methods and makes 2564 Jorge Duarte et al. its use a suitable way to predict the response of mechanical dynamic systems, particularly with a computational tool.

A bibliometric analysis of diesel engine publication from 2007 to 2018

A scientiometric analysis of the scientific production of diesel engines from 2007 to 2018 was performed using HistCite software to analyze the data collected through Web Of Knowledge. The results show that the scientific production of this topic has increased over the years, presenting its peak between 2014 and 2017, where India is the country with the highest number of publications and the Tianjun Univeristy is the institution with the highest number of publications. Most of the papers published come from developing countries whose energy matrix is based on fossil fuels, and the three journals with the most publications in this field are Fuel, Energy Conversion and Management and Energy.