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Diniz M.C.,Federal University of Santa Catarina | Pereira E.L.L.,Embraco | Deschamps C.J.,Federal University of Santa Catarina
Institution of Mechanical Engineers - 8th International Conference on Compressors and Their Systems | Year: 2013

The volumetric and isentropic efficiencies of scroll compressors are affected by the heat transfer that takes place inside the pockets during suction and compression processes. The present paper details a numerical model developed to predict the conduction heat transfer and temperature distribution of scroll wraps. The model was developed via the finite volume method and coupled to a thermodynamic model of the compression cycle. The results showed that the discharge temperature predicted with the solution of heat conduction through the scroll wraps was slightly lower than that obtained when a linear temperature profile was prescribed. It was also found that the heat transfer taking place in the metallic contact between the scrolls wraps acts to produce a linear temperature variation along their length. © The author(s) and/or their employer(s), 2013.

Icfanuti A.S.,Polytechnic University of Timisoara | Tutelea L.N.,Polytechnic University of Timisoara | Kalluf F.J.H.,Embraco | Boldea I.,Polytechnic University of Timisoara
2014 International Conference on Optimization of Electrical and Electronic Equipment, OPTIM 2014 | Year: 2014

The present paper introduces a novel two coil 1 phase stator Ferrite PM motor [1]. The main targets are reduced material and fabrication costs in a robust topology at 90% efficiency for a 35W, 1600 rpm case study. Due to complicated flux lines (with tapered airgap for self-starting) and magnetic saturation, direct FEM characterization (preliminary design) was applied. Matlab Simulink modeling for controlled dynamics which made use FEM imposed cogging torque, emf and inductance with rotor position waveforms proved smooth motor starting to rated speed for speed performance, full load in both open loop (V/f) and close loop control. © 2014 IEEE.

Pussoli B.F.,Federal University of Santa Catarina | Barbosa Jr. J.R.,Federal University of Santa Catarina | Da Silva L.W.,Embraco | Kaviany M.,University of Michigan
2010 14th International Heat Transfer Conference, IHTC 14 | Year: 2010

We present an experimental evaluation of the peripheral finned-tube heat exchanger. In this novel compact evaporator geometry, the air-side is composed by an arrangement of open-pore cells formed by radial fins whose bases are attached to the tubes and whose tips are connected to peripheral fins. Each fin arrangement is made up of six radial fins and six peripheral fins forming a hexagon-like structure. The air-side fin configuration is composed of three levels of fin arrangement, each characterized by the length of radial fin and mounted with a 30° offset from its neighboring level. Experimental data on the air-side heat transfer and pressure drop were generated in an open-loop wind tunnel calorimeter. A one-dimensional theoretical model based on the theory of porous media has also been developed to predict the thermal-hydraulic behavior of the heat exchanger. The model incorporates the actual fin geometry into the calculation of the air-side porosity. The air-side permeability is calculated according to the Kozeny-Carman model with the particle diameter definition due to Whitaker and the friction factor correlation due to Ergun. The model overpredicts the air-side thermal conductance by less than 15% for air flow rates higher than 14 L/s. The air-side pressure drop is underpredicted by the model, but still within the limits encountered in the literature. The analysis is complemented with an entropy generation minimization analysis in order to demonstrate the procedure for obtaining an optimized configuration of the heat exchanger. © 2010 by ASME.

Kalluf F.J.H.,Embraco | Icfanuti A.S.,Polytechnic University of Timisoara | Tutelea L.N.,Polytechnic University of Timisoara | Moldovan-Popa A.,Polytechnic University of Timisoara | Boldea I.,Polytechnic University of Timisoara
2015 IEEE Energy Conversion Congress and Exposition, ECCE 2015 | Year: 2015

An optimal design of internal Ferrite permanent magnet motor with embedded key FEM verification is presented with the scope to increase the efficiency of the small power motors without to use the expensive, rare earth permanent magnets. Two internal flux concentration topologies are analyzed and the geometric dimensions and performances are presented for three cases, all at 1kW rated power at 4500rpm rated speed. The 6/8 poles spoke PMSM prototype was build and test results prove an efficiency larger than 88% for a large load range. Two sensorless control methods based on active flux observer are presented with the key simulation results including acceleration, speed reversal, loading and unloading speed response. © 2015 IEEE.

Schlegel J.P.,Federal University of Santa Catarina | Batistela N.J.,Federal University of Santa Catarina | Sadowski N.,Federal University of Santa Catarina | Kuo-Peng P.,Federal University of Santa Catarina | And 4 more authors.
Journal of Microwaves, Optoelectronics and Electromagnetic Applications | Year: 2012

This paper presents an experimental comparative study of iron losses obtained by means of the Epstein frame, Ring Core and dynamometer tests with non-oriented electrical steel samples. The comparisons are qualitative and they are intended to show the importance of carrying out other tests to evaluate electrical steels in addition to the standard Epstein frame method. In industry, complex or costly tests are avoided, whenever it is possible. This study shows that the ring core test can be a low cost solution since it is effective. For the manufacturer point of view, comparing different commercial steels at purchase time with a simple process is an advantage. © 2011 SBMO/SBMag.

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