Neha

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Neha

  1. 1. NAME:- NEHA KUMARI REG.NO:-1011018058 SEMSESTER:-7TH SECTION:-D
  2. 2.         INTRODUCTION HEAT EXCHANGER NANOFLUIDS EXPERIMENTAL SETUP DATA PROCESSING RESULTS CONCLUSION REFERENCE
  3. 3.    A wide verity of industrial processes involve the transfer of heat energy. Throughout any industrial facility, heat must be added, removed or moved from one stream to another and it become major task for industrial necessity. The enhancement of heating or cooling in an industrial process may create a saving in energy, reduce process time, raise thermal rating, and improve working life of equipment. OBJECTIVE:- To enhance effective fluid thermal conductivity and heat transfer coefficient by suspending solid nanoparticles. nanoparticles
  4. 4.   HEAT EXCHNAGER is a device which is used to transfer heat between two or more fluid steams at different temperature. It is widely used in power generation, chemical processing, electronic cooling, air conditioning, refrigeration, automotive applications. Shell and tube heat exchanger
  5. 5.  1. According to the flow arrangement:Parallel flow H.E:- the fluids enters to the same end and travel parallel to one another to other side. Shell-side fluid inlet Tube side fluid inlet Tube side fluid outlet Shellside fluid outlet
  6. 6. 2. Counter flow H.E:- In counter-flow heat exchangers the fluids enter the exchanger from opposite ends. The counter current design is most efficient, in that it can transfer the most heat from the heat (transfer) medium. Shell-side fluid outlet shell- side fluid inlet Tube-side fluid inlet Tube-side fluid outlet
  7. 7.  1. 2. 3.  According to geometry construction:Shell and tube heat exchanger Plate type heat exchanger Extended surface heat exchanger Here in the experimental setup shell and tube type heat exchanger is used. And the flow of fluid is counter flow.
  8. 8.     Suspension of nanoparticles in base fluid. Nanoparticles are made of metal , oxide, carbides. Common base fluids may be water, ethylene glycol and oil. Nanofluids enhances thermal conductivity and convective heat transfer coefficient as compare to base fluid. Advantages of nanoparticles:I. High specific surface area II. High dispersion stability III. Reduced particle clogging IV. Adjustable properties, including thermal conductivity and surface wettability, by varying particle concentrations to suit different applications. 
  9. 9. 1. 2. Nanoparticle materials includes:◦ Oxide ceramics – Al2O3, CuO, TiO2 ◦ Metal carbides – SiC ◦ Nitrides – AlN, SiN ◦ Metals – Al, Cu ◦ Nonmetals – Graphite, carbon nanotubes Base fluid includes:◦ Water ◦ Ethylene- or tri-ethylene-glycols and other coolants ◦ Oil and other lubricants ◦ Bio-fluids ◦ Polymer solutions ◦ Other common fluids
  10. 10. NANOFLUID INLET WATER INLET NANO FLUID OUTLET WATER OUTLET
  11. 11.    Two series of nanofluids were prepared using two different types of nanoparticles, γ-Alumina(γ-Al2O3) and Titanium dioxide(TiO2), while water is used as a base fluid. The nanofluids with different particle volume concentrations were prepared to investigate the effect of nanoparticle concentrations on the heat transfer performance of nanofluids. The nanoparticle volume concentrations of γ-Al2O3/water and TiO2/water nanofluids vary in the range of 0.3-2% and 0.15-0.75% ,Respectively. Table1
  12. 12.   The experimental data were used to calcuclate the overall heat transfer coefficient and convective heat transfer coefficient of nanofluids with various particle volume concentration and peclet number. The heat transfer rate of nanofluid is: Q=ṁCpnf(Tout-Tin) Where, ṁ = the mass flow rate of nanofluid Cpnf= effective specific heat of nanofluid  Tout and Tin= outlet and inlet temperature of nanofluid The heat transfer coefficient of the test fluid, hi, can be calculated by the following equation:
  13. 13. Where, Di and Do = the inner and outer diameter of tubes, respectively. Ui =the overall heat transfer coefficient based on the inside tube area. hi and ho = individual convective heat transfer coefficient of fluids inside and outside the tubes respectively. kw = the thermal conductivity of the tube wall. Ui is given by:Where , where Ai = πDiL and ΔTlm is the logarithmic mean temperature difference. Peclet number is given by:Where, Pe is peclet number of particles Vm=mean velocity dp=diameter of particles αnf= diffusitivity of nanofluid
  14. 14. FIG 2: Overall heat transfer coefficient of γ-Al2O3/water nanofluid versus Peclet number for various volume concentrations. Volume concentration of γ-Al2O3 (in percentage% ) 0.30 0.50 0.75 1 2 enhancement of Overall heat transfer coefficient(Ui) (in %) 14 20 16 15 9
  15. 15. FIG3: Overall heat transfer coefficient of TiO2/water nanofluid versus Peclet number for various volume concentrations. Volume concentration of TiO2 (in percentage% ) 0.15 0.30 0.50 0.75 enhancement of Overall heat transfer coefficient(Ui) (in %) 11 24 16 13
  16. 16. FIG4 :Convective heat transfer coefficient of γ-Al2O3water nanofluid versus Peclet number for different volume concentrations Volume concentration of γ-Al2O3 (in percentage% ) 0.30 0.50 enhancement of convective heat transfer coefficient(hi) (in %) 46 FIG4:Convective heat transfer coefficient of γAl2O3/water nanofluid versus Peclet 19 56 46 38 number for different volume concentrations 0.75 1 2
  17. 17. FIG5: Convective heat transfer coefficient of TiO2/water nanofluid versus Peclet number for different volume concentrations Volume concentration of TiO2 (in percentage% ) 0.15 0.30 0.50 0.75 enhancement of convective heat transfer coefficient(hi) (in %) 20 56 33 18
  18. 18.    Addition of nanoparticles to the base fluid enhances the heat transfer performance and results in larger heat transfer coefficient than that of the base fluid at the same Peclet number. Both nanofluids have the different optimum volume concentrationin which the heat transfer characteristics show the maximum enhancement. The nanoparticle with less mean diameter (TiO2 nanoparticle) has a lower optimum volume concentration. At different nanoparticle concentrations the heat transfer enhancement of both nanofluids are not the same. TiO2/water and γ-Al2O3/water nanofluids possess better heat transfer behavior at the lower and higher volume concentrations, respectively.
  19. 19. [1]Farajollahi, S.Gh. Etemad, M. Hojjat ,Heat transfer of nanofluids in a shell and tube heat exchanger heat transfer 53(2010)12-17. [2] Sarit,K.Das., Stephen U. S. Choi, “A Review of Heat Transfer in Nanofluids”.2009 [3] M. Raja a*, R.M. Arunachalam b and S. Suresh c,Experimental studies on heat transfer of alumina/water nanofluid in a shell and tube heat exchanger.

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