Due to several engineering applications of heat transfer in confined enclosures, it has been an attractive topic for the researchers. The presented research is also an important contribution in this massive research area. Effects of a bottom heated rotating cylinder in a vertical annulus has been experimentally studied with respect to heat transfer parameters. Bottom heating of inner cylinder triggers a buoyancy-driven flow of air within the annulus and heat transfer due to this heating is studied against the rotation of the inner cylinder. Thus, a simultaneous effect of bottom heating and rotation of inner cylinder on heat transfer is inspected. The experimental setup of presented research consists of two seamless mild steel cylinders, a mild steel bottom heating plate, wireless data acquisition system and a rotational mechanism for the inner cylinder. A series of experiments are carried out for bottom heated plate temperature ranging from 313 K to 333 K and rotational Reynolds number of inner cylinder from 0 – 1660. The experimental results are presented in the form of a quantitative analysis of measured steady-state temperatures and non-dimensional parameters of heat transfer such as local Nusselt number, local Rayleigh number and Gr/ReΩ2. It is noted that the rotation of inner cylinder is effectual to enhance the heat transfer within the annulus by altering heat transport mechanisms. Moreover, the rotational effects deteriorate the influence of buoyancy at high rotational Reynolds number.
experimental investigation, heat transfer, heat transport mechanisms, vertical annulus, buoyancy-driven flow, rotating inner cylinder
 Jaluria Y. (2008). Design and optimization of thermal systems. Boca Raton. Fla. [u.a.]: CRC Press.
 Moiseeva L, Cherkasov S. (1997). Stationary free-convection heat exchange in a cylindrical tank with uniform heat supply and simultaneous heat removal through local sinks. Teplofizika Vysokikh Temperatur 35: 564-569.
 Kee R, Landram C, Miles J. (1976). Natural convection of a heat-generating fluid within closed vertical cylinders and spheres. Journal of Heat Transfer 98: 55-61. https://doi:10.1115/1.3450469
 Keyhani M, Kulacki F, Christensen R. (1983). Free convection in a vertical annulus with constant heat flux on the inner wall. Journal of Heat Transfer 105: 454-459. https://doi:10.1115/1.3245606
 Lipkea WH, Springer GS. (1968). Heat transfer through gases contained between two vertical cylinders at different temperatures. International Journal of Heat and Mass Transfer 11: 1341-1350. https://doi.org/10.1016/0017-9310(68)90179-8
 Malik AH, Alvi M, Khushnood S, Mahfouz F, Ghauri M, Shah A. (2012). Experimental study of conjugate heat transfer within a bottom heated vertical concentric cylindrical enclosure. International Journal of Heat and Mass Transfer 55: 1154-1163. https://doi.org/10.1016/j.ijheatmasstransfer.2011.09.055
 Sankar M, Park Y, Lopez JM, Do Y. (2011). Numerical study of natural convection in a vertical porous annulus with discrete heating. International Journal of Heat and Mass Transfer 54: 1493-1505. https://doi.org/10.1016/j.ijheatmasstransfer.2010.11.043
 Alipour M, Hosseini R, Rezania A. (2013). Radius ratio effects on natural heat transfer in concentric annulus. Experimental Thermal and Fluid Science 49: 135-140. https://doi.org/10.1016/j.expthermflusci.2013.04.011
 Hosseini R, Ramezani M, Mazaheri MR. (2009). Experimental study of turbulent forced convection in vertical eccentric annulus. Energy Conversion and Management 50: 2266-2274. https://doi.org/10.1016/j.enconman.2009.05.002
 Mohammed HA, Campo A, Saidur R. (2010). Experimental study of forced and free convective heat transfer in the thermal entry region of horizontal concentric annuli. International Communications in Heat and Mass Transfer 37: 739-747. https://doi.org/10.1016/j.icheatmasstransfer.2010.04.007
 Angeli D, Barozzi G, Collins M, Kamiyo O. (2010). A critical review of buoyancy-induced flow transitions in horizontal annuli. International Journal of Thermal Sciences 49: 2231-2241. https://doi.org/10.1016/j.ijthermalsci.2010.08.002
 Jeng TM, Tzeng SC, Lin CH. (2007). Heat transfer enhancement of Taylor–Couette–Poiseuille flow in an annulus by mounting longitudinal ribs on the rotating inner cylinder. International Journal of Heat and Mass Transfer 50: 381-390. https://doi.org/10.1016/j.ijheatmasstransfer.2006.06.005
 Astill K. (1964). Studies of the developing flow between concentric cylinders with the inner cylinder rotating. Journal of Heat Transfer 86: 383-391. https://doi:10.1115/1.3688703
 Ball K, Farouk B, Dixit V. (1989). An experimental study of heat transfer in a vertical annulus with a rotating inner cylinder. International Journal of Heat and Mass Transfer 32: 1517-1527. https://doi.org/10.1016/0017-9310(89)90073-2
 Lee J, Kang SH, Son YS. (1999). Experimental study of double-diffusive convection in a rotating annulus with lateral heating. International journal of Heat and Mass Transfer 42: 821-832. https://doi.org/10.1016/S0017-9310(98)00226-9
 Fu WS, Cheng CS, Shieh WJ. (1994). Enhancement of natural convection heat transfer of an enclosure by a rotating circular cylinder. International Journal of Heat and Mass Transfer 37: 1885-1897. https://doi.org/10.1016/0017-9310(94)90329-8
 Misirlioglu A. (2006). The effect of rotating cylinder on the heat transfer in a square cavity filled with porous medium. International Journal of Engineering Science 44: 1173-1187. https://doi.org/10.1016/j.ijengsci.2006.07.008
 Roslan R, Saleh H, Hashim I. (2012). Effect of rotating cylinder on heat transfer in a square enclosure filled with nanofluids. International Journal of Heat and Mass Transfer 55: 7247-7256. https://doi.org/10.1016/j.ijheatmasstransfer.2012.07.051
 Liao CC, Lin CA. (2014). Mixed convection of a heated rotating cylinder in a square enclosure. International Journal of Heat and Mass Transfer 72: 9-22. https://doi.org/10.1016/j.ijheatmasstransfer.2013.12.081
 Paroncini M, Corvaro F, Padova M. (2006). Study and analysis of the influence of a small heating source positioned on the natural convective heat transfer in a square cavity. WSEAS Transaction on Heat and Mass Transfer 1: 461-466.
 Aydin O, Yang WJ. (2000). Natural convection in enclosures with localized heating from below and symmetrical cooling from sides. International Journal of Numerical Methods for Heat & Fluid Flow 10: 518-529. https://doi.org/10.1108/09615530010338196
 Kuznetsov GV, Sheremet MA. (2011). Conjugate natural convection in an enclosure with a heat source of constant heat transfer rate. International Journal of Heat and Mass Transfer 54: 260-268. https://doi.org/10.1016/j.ijheatmasstransfer.2010.09.046
 Kang S, Choi H, Lee S. (1999). Laminar flow past a rotating circular cylinder. Physics of Fluids 11: 3312-3321. https://doi.org/10.1063/1.870190
 Özerdem B. (2000). Measurement of convective heat transfer coefficient for a horizontal cylinder rotating in quiescent air. International Communications in Heat and Mass Transfer 27: 389-395. https://doi.org/10.1016/S0735-1933(00)00119-6
 Paramane SB, Sharma A. (2009). Numerical investigation of heat and fluid flow across a rotating circular cylinder maintained at constant temperature in 2-D laminar flow regime. International Journal of Heat and Mass Transfer 52: 3205-3216. https://doi.org/10.1016/j.ijheatmasstransfer.2008.12.031
 Nagarajan R, Dhanasekaran R. (2013). Implementation of wireless data transmission in monitoring and control. in Communications and Signal Processing (ICCSP). 2013 International Conference on, 2013, pp. 83-87. https://10.1109/iccsp.2013.6577020
 Sehgal VK, Chauhan DS, Sharma R. (2008). Smart wireless temperature data logger using IEEE 802.15. 4/ZigBee protocol. In TENCON 2008-2008 IEEE Region 10 Conference, pp. 1-6. https:// 10.1109/TENCON.2008.4766744
 Borwankar AA, Ladkat AS, Mhetre MR. (2015). Thermal Transducers Analysis.
 Instruments T. (1999). LM35 Precision Centigrade Temperature Sensors. LM35 datasheet.
 Datasheet C. (2006). 2.4 GHz IEEE 802.15. 4/ZigBee-ready RF Transceiver. Chipcon products from Texas Instruments.
 Yunus AC. (2003). Heat transfer: a practical approach. MacGraw Hill, New York.