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HEAT TRANSFERCHARACTERISTICS OF A SELF ASPIRATING POROUS RADIANT BURNER FUELED WITH LPG

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This work presents the heat transfer characteristics of a self-aspirating porous radiant burner (SAPRB) that operates on the basis of an effective energy conversion method between flowing gas enthalpy and thermal radiation. The temperature field at various flame zones was measured experimentally by the help of both FLUKE IR camera and K-type thermocouples. The experimental setup consisted of a two layered domestic cooking burner, a flexible test stand attached with six K-type thermocouples at different positions, IR camera, LPG setup and a hot wire anemometer. The two layered SAPRB consisted of a combustion zone and a preheating zone. Combustion zone was formed with high porosity, highly radiating porous matrix, and the preheating zone consisted of low porosity matrix. Time dependent temperature history from thermocouples at various flame zones were acquired by using a data acquisition system and the temperature profiles were analyzed in the ZAILA application software environments.In the other hand the IR graphs were captured by FLUKE IR camera and the thermographs were analyzed in the SMARTView software environments. The experimental results revealed that the homogeneous porous media, in addition to its convective heat exchange with the gas, might absorb, emit, and scatter thermal radiation. The maximum heat transfer coefficient h, of the PRB was 40 w/m2k. The rate of heat transfer was more at the center of the burner where a combined effect of both convection & radiation might be realized.

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  • DOWNLOAD THIS BOOKS INTO AVAILABLE FORMAT (Unlimited) ......................................................................................................................... ......................................................................................................................... Download Full PDF EBOOK here { https://tinyurl.com/y6a5rkg5 } ......................................................................................................................... Download Full EPUB Ebook here { https://tinyurl.com/y6a5rkg5 } ......................................................................................................................... ACCESS WEBSITE for All Ebooks ......................................................................................................................... Download Full PDF EBOOK here { https://tinyurl.com/y6a5rkg5 } ......................................................................................................................... Download EPUB Ebook here { https://tinyurl.com/y6a5rkg5 } ......................................................................................................................... Download doc Ebook here { https://tinyurl.com/y6a5rkg5 } ......................................................................................................................... ......................................................................................................................... ......................................................................................................................... .............. Browse by Genre Available eBooks ......................................................................................................................... Art, Biography, Business, Chick Lit, Children's, Christian, Classics, Comics, Contemporary, Cookbooks, Crime, Ebooks, Fantasy, Fiction, Graphic Novels, Historical Fiction, History, Horror, Humor And Comedy, Manga, Memoir, Music, Mystery, Non Fiction, Paranormal, Philosophy, Poetry, Psychology, Religion, Romance, Science, Science Fiction, Self Help, Suspense, Spirituality, Sports, Thriller, Travel, Young Adult,
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HEAT TRANSFERCHARACTERISTICS OF A SELF ASPIRATING POROUS RADIANT BURNER FUELED WITH LPG

  1. 1. 1 HEAT TRANSFERCHARACTERISTICS OF A SELF ASPIRATING POROUS RADIANT BURNER FUELED WITH LPG Premananda Pradhan1* , Purna C. Mishra2 ,Bibhuti B. Samantaray3 , 1 Asst Professor, ITER, S'O'A University, Bhubaneswar-30, Odisha, India 2 Professor, KIIT University, Bhubaneswar-24, Odisha, India 3 M.tech Research Scholar, KIIT University, Bhubaneswar-24, Odisha, India *E-mail- pradhanpremananda@gmail.com Abstract This work presents the heat transfer characteristics of a self-aspirating porous radiant burner (SAPRB) that operates on the basis of an effective energy conversion method between flowing gas enthalpy and thermal radiation. The temperature field at various flame zones was measured experimentally by the help of both FLUKE IR camera and K-type thermocouples. The experimental setup consisted of a two layered domestic cooking burner, a flexible test stand attached with six K-type thermocouples at different positions, IR camera, LPG setup and a hot wire anemometer. The two layered SAPRB consisted of a combustion zone and a preheating zone. Combustion zone was formed with high porosity, highly radiating porous matrix, and the preheating zone consisted of low porosity matrix. Time dependent temperature history from thermocouples at various flame zones were acquired by using a data acquisition system and the temperature profiles were analyzed in the ZAILA application software environments.In the other hand the IR graphs were captured by FLUKE IR camera and the thermographs were analyzed in the SMARTView software environments. The experimental results revealed that the homogeneous porous media, in addition to its convective heat exchange with the gas, might absorb, emit, and scatter thermal radiation. The maximum heat transfer coefficient h, of the PRB was 40 w/m 2 k. The rate of heat transfer was more at the center of the burner where a combined effect of both convection & radiation might be realized. Keywords:Self-aspirating Porous Radiant Burner (SAPRB), LPG, Heat Transfer Coefficient (HTC), Transient Temperature, IR Thermography, Thermocouples 1.0 Introduction The heating systems used for domestic purposes that operate on free flame, leads to relatively low thermal efficiency. A lot of previous works are available on the use of porous media in direction of increasing thermal efficiency. Energy conversion aspects between flowing gas enthalpy and thermal radiation by using porous medium becomes an interesting approach for improving the overall performance of these systems. Proper parametric control may lead to better enhancement of burner performance.In India, LPG(liquefied petroleum gas) is the most commonly used conventional fuel [1].So as it is common in other Asian countries also. As the economy of thecountry is getting better day by day so as the standard of living of the people. The population of the India is approximately 1.25 billion so as the LPG market is very huge. Govt. of India is spending huge amount of money for subsidizing the domestic LPG cylinder price[2]. As it is a burden on the Government & ultimately on the people, different ways should be invented to increase the thermal efficiency of the conventional burners. N.K. Mishra et al.[3] has tested Medium-Scale (5-10 kw) Porous Radiant Burners for LPG Cooking Applications with a good effect. He found the PRB with 5kw thermal load yielded the maximum thermal efficiency of about 50%, which is 25% higher than the efficiency of the conventional burner also the emission are much lower than the conventional burner. V.K Pantangi et al.[4] has studied the porous radiant burner for LPG cooking application. In his study he found that the maximum thermal efficiency of PRB is found to be 68% which is 3% higher than the conventional burner with less CO & NOX emission. P.Muthukumar & P.I Shyamkumar [5] developed a novel porous radiant burner for LPG cooking applications. They have tested PRB
  2. 2. Effect Of Heat Transfer On Performance Of Porous Radiant Burner Fuelled With LPG 2 having different porosity with different equivalence ratio & wattages. The reported maximum thermal efficiency is about 75% which is 10% higher than the conventional burners. S.B Sathe et al. [6]has studied both theoretically & experimentally the thermal performance of the PRB. The results indicate that stable combustion at elevated flame speeds can be maintained in two different spatial domains: one spanning the upstream half of the porous region and the other in a narrow region near the exit plane. The heat release and radiant output are also found to increase as the flame is shifted toward the middle of the porous layer.. [7] carried out a study to investigate the lean flammability limits of the burner and the unstable flash- back/blow-out phenomena. Hayashi et al. [8] presented a three-dimensional numerical study of a two-layer porous burner for household applications. They solved the mathematical model using CFD techniques which accounted for radiative heat transport in the solid, convective heat exchange between solid and fluid. Talukdar et al. [9] presented the heat transfer analysis of a 2-D rectangular porous radiant burner. Combustion in the porous medium was modelled as a spatially- dependent heat generation zone. A 2-D rectangular porous burner was investigated by Mishra et al. [10]. Methane–air combustion with detailed chemical kinetics was used to model the combustion part. But in the above studies none has particularly experimented the thermal performance of the PRB using IR thermography. Here, in this paper we attempted to find the characterization of heat transfer of Porous radiant burner using IR Thermography. 2.0 Experimental Set-up and Test procedure A schematic of the experimental set-up used for testing the performance of PRB is shown in Fig.1. The fuel air flow rates are measured by the help of hot air anemometer with suitable control valves. The air and fuel mixtures are tested at different velocities.Air–fuel mixture moves to the burnerthrough a mixing tube made of Teflon. Three k-type thermocouples are arranged horizontally and other three k-type thermocouples are arranged vertically for the measurement of the temperature of different zones. Also the surface temperature& flame temperature are measured by the help of IR camera. All the thermocouple data are assessed by data acquisition system(DAS). DAS is connected with a computer for analysing the data in real time.The PRB consideredfor the present work is based on two-layered PMC. The twolayeredPRB consists of a preheating zone and a combustion zone. Computer HWA Burner IR Camera Vertical Thermocouple Arrangement Horizontal Thermocouple Arrangement Fig-1: Schematic of Experimental Setup. 3.0 Experimental Procedure The whole experimental procedure has been conducted in a very controlled condition. The gas velocity was measured by the hot wire anemometer. It was positioned just at the exit of the nozzle. The experimented was conducted in three different velocities viz. 3.6 m/s, 3.0 m/s and 0.4 m/s. Then the temperature data are measured by the thermocouple which has been arranged both in vertically and horizontally on the top surface of the burner. The temperature data are assessed by the data acquisition system. Also the surface and flame temperature are measured by IR camera. Then the heat transfer co-efficient h, was calculated by the following co-relation. 𝑵𝑵𝑵𝑵 = 𝟎𝟎. 𝟗𝟗𝟗𝟗𝐑𝐑𝐑𝐑𝟎𝟎.𝟑𝟑𝟑𝟑 µ ρφ Vdf =Re whereNu = Local Nusselt Number Re = Reynolds Number h = Local Heat Transfer Coefficient, W/m2 K ρ= Mass density of LPG, kg/m3 ∅f= Porosity v = Gas Velocity, m/s d = Hydraulic Diameter, m 4.0 Results and Discussion LPG DAS
  3. 3. Proceedings of the 1st International Conference on Advances in Thermal and Energy Systems (AITES-2013) Here in this experiment we have conduct the experiment in three different velocities. So the time-temperature graphs are as mentioned in the figures from 2-7. Also the IR camera pictures are attached from fig 8-9 by which indicates the surface and flame temperature. 1. At gas velocity 3.6 m/s the rate of heat transfer is more. As shown in the diagram thermocouple-3 shows temperature above 1200 ℃. Thermocouple is positioned vertically 110mm away from the surface of the burner. so it indicates high rate of convection & radiation heat transfer in that zone also the flame is totally turbulent. Similarly the thermocouple-4 which is positioned horizontally 12mm from the centre of the circular burner,which is having a radius of 38mm. It also indicates high rate of heat transfer and the maximum temperature Fig-2. Vertical Arrangement of Thermocouple at Gas Velocity 3.6 m/s Fig-3. Horizontal Arrangement of Thermocouple at Gas Velocity 3.6 m/s 0 200 400 600 800 1000 1200 1400 0 100 200 300 400 500 600 700 Thermocouple-1 Thermocouple-2 Thermocouple-3 0 200 400 600 800 1000 1200 0 100 200 300 400 500 600 700 800 Thermocouple-4 Thermocouple-5 Thermocouple-6
  4. 4. Effect Of Heat Transfer On Performance Of Porous Radiant Burner Fuelled With LPG 4 Fig-4. Vertical Arrangement of Thermocouple at Gas Velocity 3.0 m/s Fig-5. Horizontal Arrangement of Thermocouple at Gas Velocity 3.0 m/s Fig-6. Vertical Arrangement of Thermocouple at Gas Velocity 0.4 m/s 0 200 400 600 800 1000 1200 0 200 400 600 800 1000 Thermocouple-1 Thermocouple-2 Thermocouple-3 0 100 200 300 400 500 600 700 800 900 1000 0 200 400 600 800 1000 1200 Thermocouple-4 Thermocouple-5 Thermocouple-6 0 50 100 150 200 250 300 350 0 100 200 300 400 500 600 700 Thermocouple-1 Thermocouple-2 Thermocouple-3
  5. 5. Proceedings of the 1st International Conference on Advances in Thermal and Energy Systems (AITES-2013) Fig-7. Horizontal Arrangement of Thermocouple at Gas velocity 0.4 m/s Fig-8. Temperature of the Burner surface Measured By IR Camera. 0 100 200 300 400 500 600 700 800 0 100 200 300 400 500 600 700 Thermocouple-4 Thermocouple-5 Thermocouple-6
  6. 6. Effect Of Heat Transfer On Performance Of Porous Radiant Burner Fuelled With LPG 6 Fig-9. Temperature of the Random Flame Measured by IR Camera. attained is very close to 1000 ℃. So by calculating, the h was found to be 38.598 w/m2 k. 2. At gas velocity 3.0 m/s the rate of heat transfer is less as compared to the previous case. As shown in the diagram thermocouple-3 shows temperature around 1000 ℃. Thermocouple is positioned vertically 65mm away from the surface of the burner. Similarly the thermocouple-4 which is positioned horizontally 12mm from the centre of the circular burner,which is having a radius of 38mm attains a temperature around 950 ℃. So in both the cases the thermocouple-3 and thermocouple-4 indicates that the rate of heat transfer is more at the center of the burner. The heat transfer co-efficient is found to be 32.165 w/m2 k. 3. At gas velocity 0.4 the heat transfer characteristics are found to be the same as the previous two and the h is found to be 4.288 w/m2 k. 5.0 CONCLUSIONS From the above experiment we conclude that the performance of the PRB can be optimized if we can control the parameters in a proper manner. The rate of heat transfer was found to be very good in different velocity range with maximum temperature reaches at 1247 ℃. It still can go up to more if we can have a advanced experimental setup. The maximum heat transfer co-efficient was found to be 38.59 w/m2k. So by controlling the parameter & optimizing the process we can find more amount of heat transfer in the PRB which ultimately saves energy and can be very useful for LPG cooking application. REFERENCES [1] D’SaAntonette, Narasimha Murthy KV. Report on the use of LPG as a domestic cooking fuel option in India. Int Energy Initiative, http://www.iei-asia.org/ IEIBLR-LPG- Indiahomes Report.pdf.2004. [2] Mnril R. LPG in India subsidy with a purpose, In: WLPGA – North Africa LPG summit 20th May 2010. [3] Mishra, N. K., Muthukumar, P., Mishra, S.C., 2013.Performance Tests on Medium-Scale Porous Radiant Burners for LPG Cooking Applications, International Journal of Emerging Technology and Advanced Engineering, Volume 3, Special Issue 3: ICERTSD 2013, Feb 2013, pages 126-130, ISSN 2250-2459. [4] Pantangi, V.K., Mishra, S.C., Muthukumar, P. and Reddy, R., 2011, “Studies of PRBs for Cooking Application”, Energy, 36:6074-6080.
  7. 7. Proceedings of the 1st International Conference on Advances in Thermal and Energy Systems (AITES-2013) [5] Muthukumar, P., Shyamkumar, P.I. 2013, " Development of a novel porous radiant burner for LPG cooking application", Fuel, 112 ; 562-566 [6] Sathe, S.B., Kulkarni, M.R., Peck R.E., and Tong T.W,. "An Experimental and Theoretical study of porous radiant burner performance". Twenty third Symposium (Internal) on Combustion/ The Combustion Institute,1990/pp. 1011-1018. [7] Akbari, M. H., Riahi, P. and Roohi, R., 2009, “Lean flammability limits for stable performance with a porous burner”, Applied Energy; 86:2635– 43. [8] Hayashi, T.C., Malico, I. and Pereira, J.C.F. , 2004,“Three-dimensional modelling of a two-layer porous burner for household applications”, Computers and Structures; 82:1543–50. [9] Talukdar, P., Mishra, S.C., Trimis, D. and Durst, F., 2004, “Heat transfer characteristics of porous radian burner under the influence of a 2-D radiation field”, Journal of Quantitative Spectroscopy and Radiant Transfer, 84: 527-537. [10] Mishra, S.C., Steven, M., Nemoda, S., Talukdar, P., Trimis, D. and Durst, F., 2006, “Heat transfer analysis of a two-dimensional rectangular porous radiant burner”, Int. Communications in Heat Mass Transfer, 33: 467-74.

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