An experimental study about the heat transfer rate and intermediate surface temperature analysis through traditional method of composite wall heat transfer

2020 ◽  
Author(s):  
R.B. Manoram ◽  
S. Dinesh Krishnaa ◽  
M. Baranitharan ◽  
K. Gokulakrishnan ◽  
M. Dinesh Krishna ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Surface Temperature ◽  
Heat Transfer Rate ◽  
Traditional Method ◽  
Transfer Rate ◽  
Wall Heat Transfer ◽  
Temperature Analysis ◽  
Composite Wall ◽  
Intermediate Surface

The Effect of Hot-Streaks on HP Vane Surface and Endwall Heat Transfer: An Experimental and Numerical Study

2005 ◽  
Author(s):  
T. Povey ◽  
K. S. Chana ◽  
T. V. Jones ◽  
J. Hurrion
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Cooling System ◽  
Numerical Study ◽  
Inlet Temperature ◽  
Temperature Profiles ◽  
Wall Heat Transfer ◽  
Hot Streak ◽  
End Wall

Pronounced non-uniformities in combustor exit flow temperature (hot-streaks), which arise because of discrete injection of fuel and dilution air jets within the combustor and because of end-wall cooling flows, affect both component life and aerodynamics. Because it is very difficult to quantitatively predict the affects of these temperature non-uniformities on the heat transfer rates, designers are forced to budget for hot-streaks in the cooling system design process. Consequently, components are designed for higher working temperatures than the mass-mean gas temperature, and this imposes a significant overall performance penalty. An inadequate cooling budget can lead to reduced component life. An improved understanding of hot-streak migration physics, or robust correlations based on reliable experimental data, would help designers minimise the overhead on cooling flow that is currently a necessity. A number of recent research projects sponsored by a range of industrial gas turbine and aero-engine manufacturers attest to the growing interest in hot-streak physics. This paper presents measurements of surface and end-wall heat transfer rate for an HP nozzle guide vane (NGV) operating as part of a full HP turbine stage in an annular transonic rotating turbine facility. Measurements were conducted with both uniform stage inlet temperature and with two non-uniform temperature profiles. The temperature profiles were non-dimensionally similar to profiles measured in an engine. A difference of one half of an NGV pitch in the circumferential (clocking) position of the hot-streak with respect to the NGV was used to investigate the affect of clocking on the vane surface and end-wall heat transfer rate. The vane surface pressure distributions, and the results of a flow-visualisation study, which are also given, are used to aid interpretation of the results. The results are compared to two-dimensional predictions conducted using two different boundary layer methods. Experiments were conducted in the Isentropic Light Piston Facility (ILPF) at QinetiQ Farnborough, a short duration engine-size turbine facility. Mach number, Reynolds number and gas-to-wall temperature ratios were correctly modelled. It is believed that the heat transfer measurements presented in this paper are the first of their kind.

Instantaneous Local Heat Flux Measurements in a Small Utility Engine

2009 ◽  
Author(s):  
Terry Hendricks ◽  
Jaal Ghandhi ◽  
John Brossman
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Numerical Model ◽  
Surface Temperature ◽  
Heat Transfer Rate ◽  
Surface Heat Flux ◽  
Transfer Rate ◽  
Surface Heat ◽  
High Load ◽  
Flux Measurements

Heat flux measurements were performed in an air-cooled utility engine using a fast-response coaxial-type surface thermocouple. The surface heat flux was calculated using both analytical and numerical models. The heat flux was found to be a strong function of engine load. The peak heat flux and initial heat flux rise rate increase with engine load. The measured heat flux data were used to estimate a global heat transfer rate, and this was compared with the heat transfer rate calculated by a single-zone heat release analysis. The measured values of heat transfer were higher than the calculated values largely because of the lack of spatial averaging. The high load data showed an unexplainable negative heat flux during the expansion stroke while the gas temperature was still high. A 1D and 2D finite difference numerical model utilizing an adaptive timestep Crank-Nicholson (CN) integration routine was developed to investigate the surface temperature measurement. Applying the measured surface temperature profile to the 1D model, the resultant surface heat flux showed excellent agreement with the analytical inversion solution and captured the reversal of the energy flow back into the cylinder during the expansion stroke. The 2D numerical model was developed to observe transient lateral conduction effects within the probe and incorporated the various materials used in the construction and assembly of the heat flux sensor. The resulting average heat flux profile for the test case is shown to be slightly higher in peak and longer in duration when compared with the results from the 1D analytical inversion, and this is attributed to contributions from the high thermal diffusivity constituents in the sensor. Furthermore, the negative heat flux at high load was not eliminated suggesting that factors other than lateral conduction may be affecting the measurement accuracy.

scholarly journals Experimental Study for Counter to Cross Flow Air Cooled Heat Exchanger in Concentric Tube using Rectangular Copper Fins Spacing with Internal Spiral Grooving

2021 ◽  
pp. 203-208
Author(s):  
Rakesh Kumar Tiwari ◽  
Ajay Singh ◽  
Parag Mishra
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Natural Convection ◽  
Heat Exchanger ◽  
Forced Convection ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Cross Flow ◽  
Variable Number ◽  
Air Cooled Heat Exchanger

In this manuscript we have presented eight variation of Air-Cooled Heat Exchanger (ACHE) design with internal spiral grooving, all of them are having variable number of rectangular copper fins with different distances between the fins. In the proposed design we get the value of heat transfer rate of a counter to cross flow ACHE is 7833.77 watt, 4068.13 watt, 2736.95 watt, 2161.49 watt, 1802.89 watt, 1546.44 watt, 1336.51 watt and 1165.74 watt in natural convection (without fan) for 0.5 cm, 1.0 cm, 1.5 cm, 2.0 cm, 2.5 cm, 3.0 cm, 3.5 cm and 4.0 cm respectively. Then again, value of rate of heat transfer in forced convection (with fan) are 8007.46 watt, 4084.81 watt, 2754.69 watt, 2205.98 watt, 1809.24 watt, 1555.39 watt, 1352.88 watt and 1172.78 watt for 0.5 cm, 1.0 cm, 1.5cm, 2.0 cm, 2.5 cm, 3.0 cm, 3.5 cm and 4.0 cm respectively.

Heat Transfer Enhancement of Car Radiator Using Al₂ O₃ / Water Nanofluid in the Presence of Electric Field; an Experimental Study

2020 ◽  
pp. 15-24
Author(s):  
Koorosh Goudarzi ◽  
H. Jamali ◽  
V. Kalaei
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Electric Field ◽  
Heat Transfer Enhancement ◽  
Heat Transfer Rate ◽  
Thermal Performance ◽  
Transfer Rate ◽  
Pure Water ◽  
Transfer Enhancement ◽  
Fan Speed

In this experimental study, Aluminums Oxide (Al2O3) in Pure Water (PW) as nanofluid was used for heat transfer enhancement in car radiator together with electric field. Electric field with different voltage 8, 11, 14 kV and nanofluids with volume concentrations of 0.08%, 0.5% and 1% were investigated. From the experiments, it was found that the unit with electric field pronounced better heat transfer rate, especially at low fan speed. In addition heat transfer coefficient and heat transfer rate in engine cooling system increased with the usage of nanofluids Al2O3/PW compared to Pure Water alone. With the use of nanofluid with concentration of 1% and electric field for fan speed 600 and 1200 rpm, thermal performance factors were in a range between, 1.8–3.2 and 1.6–1.74, respectively. Thermal performance factor is more than 1 in all of cases, and it can be concluded that this technique can be used in car radiators to improve heat transfer.

scholarly journals Formation of multiple combustion fronts in an imbert downdraft gasification reactor

2021 ◽  
Vol 302 ◽  
pp. 01007
Author(s):  
Kittipass Wasinarom ◽  
Sarawut Sungworagarn ◽  
Prasan Sathitruangsak ◽  
Kasemsil Onthong
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Heat Transfer Rate ◽  
Oxygen Concentration ◽  
Temperature Rise ◽  
Combustion Front ◽  
Transfer Rate ◽  
Air Inlet ◽  
Air Supply

The experimental study of downdraft gasification was performed in this paper. The operation which led to the formation of the second combustion front was pointed out. In this situation, both combustion fronts will lose their intensity and finally be extinguished. The operation was unintentionally stopped. It was revealed that the combustion front propagated upward in the reactor after starting the test. While it was about to reach the air inlet nozzle, the second combustion front was detected by an abrupt temperature rise of the thermocouple above the air supply nozzle. After the formation of the second combustion front, both fronts started to lose their intensity which indicated by the decrease in temperature corresponding with their locations. It was possible that the second combustion front would dilute the oxygen concentration supplied to the first combustion front. The decreasing temperature of the first combustion front reduced the heat transfer rate to the second combustion front. Finally, both combustion fronts were extinguished. The operation was unintentionally stopped.

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