Onuralp Uluer

An Experimental Investigation of the Cold Mass Fraction, Nozzle Number, and Inlet Pressure Effects on Performance of Counter Flow Vortex Tube

This paper discusses the experimental investigation of vortex tube performance as it relates to cold mass fraction, inlet pressure, and nozzle number. The orifices have been made of the polyamide plastic material. Five different orifices, each with two, three, four, five and six nozzles, respectively, were manufactured and used during the test. The experiments have been conducted with each one of those orifices shown above, and the performance of the vortex tube has been tested with air inlet pressures varying from 150 kPa to 700 kPa with 50 kPa increments and the cold mass fractions of 0.5―0.7 with 0.02 increments. The energy separation has been investigated by use of the experimentally obtained data. The results of the experimental study have shown that the inlet pressure was the most effective parameter on heating and the cooling performance of the vortex tube. This occurs due to the higher angular velocities and angular momentum conservation inside the vortex tube. The higher the inlet pressure produces, the higher the angular velocity difference between the center flow and the peripheral flow in the tube. Furthermore, the higher velocity also means a higher frictional heat formation between the wall and the flow at the wall surface of the tube. This results in lower cold outlet temperatures and higher hot outlet temperatures.

An Experimental Investigation of Performance and Exergy Analysis of a Counterflow Vortex Tube Having Various Nozzle Numbers at Different Inlet Pressures of Air, Oxygen, Nitrogen, and Argon

An experimental investigation has been carried out to determine the thermal behavior of cooling fluid as it passes through a vortex tube and the effects of the orifice nozzle number and the inlet pressure on the heating and cooling performance of the counterflow type vortex tube (RHVT). Experiments have been performed using oxygen (O 2 ), nitrogen (N 2 ), and argon (Ar). Five orifices have been fabricated and used during the experimental study with different nozzle numbers of 2, 3, 4, 5, and 6. The orifices used at these experiments are made of the polyamide plastic material. The thermal conductivity of polyamide plastic material is 0.25 W/m K. To determine the energy separation, the inlet pressure values were adjusted from 150 kPa to 700 kPa with 50 kPa increments for each one of the orifices and each one of the studied fluids. The vortex tube that was used during the experiments has L/D ratio of 15 and the cold mass fraction was held constant at 0.5. As a result of the experimental study, it is determined that the temperature gradient between the cold and hot exits is decreased depending on the orifice nozzle number increase. Exergy analyses have been realized for each one of the studied fluids under the same inlet pressures with the experiments (P i = 150-700). The exergy efficiency of the vortex tube is more affected by inlet pressure than nozzle number.

Statistical Assessment of Counter-Flow Vortex Tube Performance for Different Nozzle Numbers, Cold Mass Fractions, and Inlet Pressures Via Taguchi Method

Abstract In this article, the effect and optimization of process parameters in a counter-flow vortex tube on temperature difference were investigated through the Taguchi method. The experiments were planned as per Taguchis L27 orthogonal array with each experiment performed under different conditions of inlet pressure, nozzle number, and cold mass fraction. By means of analysis of variance and regression analysis, the effects of factors and their interactions on temperature difference were determined and modeled with a correlation coefficient of 93.5%. Accordingly, it was observed that temperature difference goes up with the increase in inlet pressure, and the cold mass fraction and decreases with the increase in nozzle number. In addition, the optimum settings of process parameters maximizing the temperature difference are an inlet pressure of 650 kPa, a nozzle number of 2, and a cold mass fraction of 0.7. Finally, confirmation tests verified that the Taguchi method was successful in the assessment of vortex tube parameters for temperature difference.

The Effects of Orifice Nozzle Number on Heating and Cooling Performance of Vortex Tubes: An Experimental Study

Abstract In this study, the effects of the orifice nozzle number and the inlet pressure on the heating and cooling performance of the counter flow type vortex tube is investigated experimentally. The orifices are produced using the polyamide plastic material. Five orifices with 2, 3, 4, 5, and 6 nozzles are manufactured. In this study, air is used as a fluid. In the experiments, for each of the orifices, inlet pressures were adjusted from 150 kPa to 700 kPa with 50 kPa increments and the energy separation was investigated. During the experiments, cold mass fraction of the vortex tube that L/D ratio is 15, is held constant at 0.5. At the end of the experimental study, it is noted that the temperature gradient between the cold and hot fluid is decreased with increasing of the orifice nozzle number.

The Numerical Analysis of a Mold Cavity Filling Using the Finite Control Volume Method and Comparison to the Experimental Results

One of the most complicated subjects of the injection molding is the flow analysis. The flow of the plastic depends on the structure of the plastic material and the geometry of the mold cavity and the injection process parameters. The flow analysis and the simulations are achieved according to the numerical solution of the non linear differential governing equations. In this study, the Navier-Stokes equations are solved using the Finite Control Volume Method. The staggered grid system is used for the Full Implicit discretization method and SIMPLE algorithm is preferred for the calculation of the pressure. The Boussinesq approach is applicated to determine the density variations and the Power Law viscosity model is choosen. The melt flow is analyzed by Phoenics code. Both numerical analysis and the experiments have been realized for the same processing conditions and the same plastic material. HDPE is studied as a plastic material. It is shown that the theoretical and the experimental results are in good agreement.

A Study on Some Factors Affecting on CO 2 Curing of Expanded Perlite Based Thermal Insulation Panel

Energy, which is needed for every aspect of life, plays a key role for the development of the countries. Countries need to use energy efficiently to be advantageous in the global competition and ensure the sustainable development. Countries using the energy efficiently succeed economically and have leading the field in the competition. The purpose of this study is to put forward to the role and importance of energy efficiency for the sustainable development of the countries. In this study, energy efficiency has been examined conceptually considering the studies in the literature and the role and importance of energy efficiency has been emphasized for the sustainable development of the countries.