VORTEX TUBE REFRIGERATION SYSTEM BASED ON COMPRESSED AIR

Transcription

1 International Journal of Mechanical Engineering and Technology (IJMET) Volume 6, Issue 7, July 2015, pp , Article ID: Available online at ISSN Print: and ISSN Online: IAEME Publication VORTEX TUBE REFRIGERATION SYSTEM BASED ON COMPRESSED AIR Tejshree Bornare, Abhishek Badgujar and Prathamesh Natu Department of Mechanical Engineering, KGCE, Karjat, INDIA ABSTRACT Refrigeration plays an important role in developing countries, primarily for the preservation of food, medicine, and for air conditioning. Conventional refrigeration systems are using Freon as refrigerant. As they are the main cause for depletion of ozone layer, extensive research work is going on alternate refrigeration systems. Vortex tube is a non conventional cooling device, having no moving parts which will produce cold air and hot air from the source of compressed air without affecting the environment. When a high pressure air is tangentially injected into vortex chamber a strong vortex flow will be created which will be split into two air streams, one hot stream and the other is cold stream at its ends. An experimental investigation is to be performed in order to realize the behavior of a vortex tube system. In this work attention has to be focused on the classification of the parameters affecting vortex tube operation. The effective parameters are divided into two different types, namely geometrical and thermo-physical ones. A reliable test rig is to be designed and constructed to investigate the effect of geometrical parameters i.e. diameter and length of main tube, diameter of outlet orifice, shape of entrance nozzle.thermophysical parameters are inlet gas pressure, type of gas, cold gas mass ratio and moisture of inlet gas. Keywords: Refrigeration, Vortex tube, Cooling, Pressure, Gas, Test Cite this Article: Tejshree Bornare, Abhishek Badgujar and Prathamesh Natu, Vortex Tube Refrigeration System Based on Compressed Air. International Journal of Mechanical Engineering and Technology, 6(7), 2015, pp editor@iaeme.com

2 Tejshree Bornare, Abhishek Badgujar and Prathamesh Natu 1. INTRODUCTION Refrigeration and Air-Conditioning play an important role in modern Human Life. They not only offer comfortable and healthy living environments but also become a necessity of life to survive for server weather. The accelerated technical development and economic growth of most counties during the last century has produced sever environmental problems. Approximately 66 million new refrigerator and freezers units are manufactured worldwide each year and hundreds of millions are currently in use. It is anticipated that the production of refrigerator and freezer and the inventory will substantially increase in the near future due to an increased demand is especially in developing countries. In order to protect the environment it is important that the non-cfc refrigeration system designs are to be incorporated as early as possible and retrofits are to be developed for existing refrigerators and freezers using suitable substitute refrigerants. Probably the most widely used current application of refrigeration are for air conditioning of private homes and public buildings, and refrigerating foodstuffs in homes, restaurants and large storage warehouses. The use of refrigerators in kitchen for storing fruits and vegetables has allowed adding fresh salads to the modern diet year round, and storing fish and meats safely for long periods. By using vortex tube refrigeration system both hot and cold cooling effect can be produced without any harm to the environment. This is the main advantage of Vortex tube refrigeration system based on Compressed air. 2. LITERATURE REVIEW The Vortex Tube, is a mechanical device that separates a compressed gas into hot cold streams. It does not have any moving parts. Pressurized gas is injected tangentially into a swirl chamber and accelerates to a high rate of rotation. Due to the conical nozzle at the end of the tube, only the outer shell of the compressed air is allowed to escape at the end. The remainder of the air is forced to return in an inner vortex of reduced diameter within the outer vortex. When used to refrigerate, heat-sinking the whole vortex tube is helpful. Vortex tubes can also be cascaded. The cold (or hot) output of one can be used to pre-cool (or pre-heat) the air supply to another vortex tube. Vortex Refrigeration is a highly sophisticated system that contains a Vortex Tube which due to centrifugal force expels the internal energy of the air while the air at the center core is made cooler. In this type of system the effectiveness is too low but considering its small size this can t be ruled off. This is used as personal cooling system in suits that are designed to withstand heat. 3. WORKING Compressed air at high pressure enters the vortex tube through tangential nozzle where the flow gets accelerated. Due to tangential entry, the air has high velocity and rotates at very high speed. Thus the air has whirling or vortex motion by using six slot brass spinner in vortex chamber. The end of the cold pipe, which built up with the vortex chamber, is fitted with a washer that has the half the diameter of the pipe. Washers with different diameter are also used to adjust the system. Thus cold air is produced at right end and hot air is produced at the left end of the vortex tube editor@iaeme.com

3 Vortex Tube Refrigeration System Based on Compressed Air Figure 1 Actual picture of the Vortex Tube Figure 2 Actual diagram of 6 slot Spinner Figure 3 Actual diagram of Restrictor 99 editor@iaeme.com

4 Tejshree Bornare, Abhishek Badgujar and Prathamesh Natu 4. EXPERIMENTATION The experimental setup consists of compressor, vortex tube and temperature indicator. A stop valve at the compressor reservoir exit controls the inlet air to the vortex chamber. The inlet pressure is measured using pressure gauge. The temperatures of the air at inlet, at cold end, at hot end and ambient air are measured using thermocouple. 5. FIGURES AND TABLES: 5.1Calculations 1. Pressure Range = (9-8 bar) 2. = Area = (/4)*D^2 4. T(atm) = T(inlet) = Velocity = 15.6 m/s 6. Discharge (q) = 4.41*10-4 m 3 /s 7. Mass Flow Rate (m) = 5.403*10-4 kg/s 8. Cooling Effect (q) = 11.94*10-3 m 3 /s 9. Heating Effect (Q) = 3.79*10-3 m 3 /s Table No 5.1 Difference And Velocity: Sr. No. Pressure Range (bar) Inlet ( ) Hot End ( ) Cold End ( ) Difference Velocity (m/s) Table No 5.2 Cooling Effect: Sr. No. Pressure Range (bar) CoolingEffect Q=m*Cp* T editor@iaeme.com

5 Vortex Tube Refrigeration System Based on Compressed Air Table No 5.3 Heating Effect: Sr. No. Pressure Range (bar) HeatingEffect Q=m*Cp* CONCLUSION A simple model of the Vortex Tube is described that captures the physics related to one possible operating mechanism. The model is shown to faithfully reproduce a limited set of data if two empirical parameters are adjusted. The semi-empirical model is subsequently used to evaluate the potential performance benefit associated with replacing the throttling valve in a refrigeration system with an approximately optimized Vortex Tube. An experimental study on the temperature separation in the Vortex Tube has been carried out and this research finding can be summarized as follows 1. difference increases with increase in Inlet Pressure. 2. Availability destruction decreases with increase in tube length due to the increase in temperature difference. 3. Efficient working point of the existing design is at a cold mass fraction 0.84 for an inlet pressure of 5bar. 4. Availability destruction is less in the case of Vortex Tube operation with two nozzles than with one nozzle due to the increase in temperature difference. 5. The increase of the number of inlet nozzles led to higher temperature separation in the Vortex Tube. 6. Using the tube with insulation to reduce energy loss to surroundings gave a higher temperature separation in the tube than that without insulation around 2-3 for the cold tube and 2-5 for the hot Tube. 7. A small cold orifice (d/d=0.4) yielded higher backpressure with a large cold orifice (d/d=0.7, 0.8, and 0.9) allowed higher tangential velocities into the cold tube, resulting in lower thermal energy separation in the tube. 8. The performance of a conventional vapor compression refrigeration cycle cannot be augmented through the application of a Vortex Tube because no temperature separation can occur beneath the vapor dome. 9. The performance of a vapor compression cycle operating in the near supercritical region, such as carbon dioxide refrigeration cycle, is negligibly increased by the application of a Vortex Tube editor@iaeme.com

6 Tejshree Bornare, Abhishek Badgujar and Prathamesh Natu 7. REFERENCES [1] PRABAKARAN.J, Effect of Diameter of Orifice and Nozzle on the performance of Counter flow Vortex tube, IJEST. [2] S.C Arora and S. Domkundwar, A course in refrigeration and air conditioning, Dhanapat Rai & Sons Publications, 3rd Edition, 2009, Delhi 229. [3] R.S.Khurmi and J.K.Gupta Refrigeration and Air Conditioning, S.Chand publication, 4th Edition, 2008, Delhi pp [4] Volkan Kirmaci, Energy analysis and performance of a counter flow Ranque Hilsch vortex tube having various nozzle numbers at different inlet pressures of oxygen and air, Elsevier journal, May [5] Soni and Thomson, Optimal design of RanqueHilsch vortex tube. ASME J. Heat transfer. 94(2), 1975, pp [6] Alka Bani Agrawal and Vipin Shrivastava, Retrofitting of vapour compression refrigeration trainer by an eco-friendly refrigerant. Indian J. Sci. Technol. 3(4) This issue. Domain: [7] J. Prabakaran., S. Vaidyanatha., Effect of Orifice and Pressure of Counter Flow Vortex Tube, IJST, 3(4), 2010, [8] R. Shamsoddini, A. H. Nezhad, Numerical analysis of the effects of nozzles number on the flow and power of cooling of a vortex tube, International Journal of Refrigeration, 33 (4), 2010, [9] Peethambaran K M, Asok Kumar N and John T D, Adsorption Refrigeration System for Automobiles an Experimental Approach International Journal of Mechanical Engineering & Technology, Vol 3 (2), 2012, pp [10] S. Nimbalkar and M. R Muller., An experimental investigation of the optimum geometry for the cold end orifice of a vortex tube, Applied Thermal Engineering, 29(2-3), 2009, pp editor@iaeme.com