Determination of the Heat Transfer Rate and Friction Coefficient in Cross-Flow Forced Convection

2017 ◽  
Author(s):  
Fernanda Disconzi ◽  
JOSÉ VIRIATO COELHO VARGAS ◽  
Leonardo Cavalheiro Martinez
Keyword(s):  
Heat Transfer ◽  
Friction Coefficient ◽  
Forced Convection ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Cross Flow

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.

Numerical Study of Fluid Flow and Heat Transfer Enhancement of Nanofluids over Tube Bank

2013 ◽  
Vol 388 ◽  
pp. 149-155 ◽  
Author(s):  
Mazlan Abdul Wahid ◽  
Ahmad Ali Gholami ◽  
H.A. Mohammed
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Cross Flow ◽  
Bulk Temperature ◽  
Compact Heat Exchanger ◽  
Pure Fluid ◽  
Tube Banks

In the present work, laminar cross flow forced convective heat transfer of nanofluid over tube banks with various geometry under constant wall temperature condition is investigated numerically. We used nanofluid instead of pure fluid ,as external cross flow, because of its potential to increase heat transfer of system. The effect of the nanofluid on the compact heat exchanger performance was studied and compared to that of a conventional fluid.The two-dimensional steady state Navier-Stokes equations and the energy equation governing laminar incompressible flow are solved using a Finite volume method for the case of flow across an in-line bundle of tube banks as commercial compact heat exchanger. The nanofluid used was alumina-water 4% and the performance was compared with water. In this paper, the effect of parameters such as various tube shapes ( flat, circle, elliptic), and heat transfer comparison between nanofluid and pure fluid is studied. Temperature profile, heat transfer coefficient and pressure profile were obtained from the simulations and the performance was discussed in terms of heat transfer rate and performance index. Results indicated enhanced performance in the use of a nanofluid, and slight penalty in pressure drop. The increase in Reynolds number caused an increase in the heat transfer rate and a decrease in the overall bulk temperature of the cold fluid. The results show that, for a given heat duty, a mas flow rate required of the nanofluid is lower than that of water causing lower pressure drop. Consequently, smaller equipment and less pumping power are required.

Thermal Assessment of Forced Convection Through Metal Foam Heat Exchangers

2011 ◽  
Vol 133 (11) ◽  
Author(s):  
A. Tamayol ◽  
K. Hooman
Keyword(s):  
Heat Transfer ◽  
Thermal Resistance ◽  
Forced Convection ◽  
Heat Transfer Rate ◽  
Heat Exchangers ◽  
Transfer Rate ◽  
Metal Foam ◽  
Convection Heat Transfer ◽  
Geometrical Parameters ◽  
Convection Heat

Using a thermal resistance approach, forced convection heat transfer through metal foam heat exchangers is studied theoretically. The complex microstructure of metal foams is modeled as a matrix of interconnected solid ligaments forming simple cubic arrays of cylinders. The geometrical parameters are evaluated from existing correlations in the literature with the exception of ligament diameter which is calculated from a compact relationship offered in the present study. The proposed, simple but accurate, thermal resistance model considers: the conduction inside the solid ligaments, the interfacial convection heat transfer, and convection heat transfer to (or from) the solid bounding walls. The present model makes it possible to conduct a parametric study. Based on the generated results, it is observed that the heat transfer rate from the heated plate has a direct relationship with the foam pore per inch (PPI) and solidity. Furthermore, it is noted that increasing the height of the metal foam layer augments the overall heat transfer rate; however, the increment is not linear. Results obtained from the proposed model were successfully compared with experimental data found in the literature for rectangular and tubular metal foam heat exchangers.

Optimally Staggered Finned Circular and Elliptic Tubes in Turbulent Forced Convection

2006 ◽  
Vol 129 (5) ◽  
pp. 674-678 ◽  
Author(s):  
R. L. S. Mainardes ◽  
R. S. Matos ◽  
J. V. C. Vargas ◽  
J. C. Ordonez
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
External Flow ◽  
Geometric Optimization ◽  
Total Heat Transfer ◽  
Finned Tubes ◽  
Optimization Study ◽  
Dimensionless Heat

This work presents an experimental geometric optimization study to maximize the total heat transfer rate between a bundle of finned tubes in a given volume and a given external flow both for circular and elliptic arrangements, for general staggered configurations. The results are reported for air as the external fluid, in the range 2650⩽Re2b⩽10,600, where 2b is the smaller ellipse axis. Experimental optimization results for finned circular and elliptic tubes arrangements are presented. A relative heat transfer gain of up to 80% (Re2b=10,600) is observed in the elliptic arrangement optimized with respect to tube-to-tube spacings, as compared to the optimal circular one. A relative heat transfer gain of 80% is observed in the three-way optimized elliptic arrangement in comparison with the two-way optimized circular one; i.e., with respect to tube-to-tube and fin-to-fin spacings. An empirical correlation for the three-way optimized configuration was obtained to evaluate the resulting maximized dimensionless heat transfer rate.

scholarly journals Analytical Performance Analysis of Cross Flow Louvered Fin Automobile Radiator

2018 ◽  
Vol 172 ◽  
pp. 02003
Author(s):  
R Badgujar Pankaj ◽  
S Rangarajan ◽  
S. R Nagaraja
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Cross Flow ◽  
Maximum Deviation ◽  
Side Pressure ◽  
Proposed Model ◽  
Louvered Fin ◽  
Louvered Fins

The objective of the present paper is to propose an analytical model for calculating performance parameter of a radiator having rectangular tube with louvered fins. The theoretical effectiveness, heat transfer rate, outlet temperatures of both air and coolant are determined using effectiveness-NTU method. The coolant and air side pressure drop is also calculated. The proposed procedure is validated with experimetal results available in the literature and the GT model. It is found that the maximum deviation in the heat transfer rate calculated from proposed model is 10.97%, the coolant and air outlet temperatures is 2.75% and variation in pressure drop is about 3.29%.

The Performance of a Scaled-Down Fluidized Loop Seal

2003 ◽  
Author(s):  
Andreas Johansson ◽  
Filip Johnsson ◽  
Bengt-A˚ke Andersson
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Scaling Laws ◽  
Tube Bundle ◽  
Flow Behavior ◽  
Cross Flow ◽  
Operating Conditions ◽  
Cfb Boiler ◽  
Super Heater

This work investigates the solids cross flow in a super-heater tube bundle immersed in the loop seal of a cold CFB unit. The loop seal and the tube bundle are scaled to a 1/3rd of the size of a loop seal and a super-heater located in a 30 MWth CFB boiler. The simplified scaling laws proposed by Glicksman et al. [1] are applied to the flow in the seal. The loop seal was built into an existing CFB unit with riser dimensions 0.7 m × 0.12 m × 8.5 m. The riser is not scaled but the pressure distribution in the CFB loop is similar to that in the boiler. The solids flow through the tube bundle was studied by means of visual observations, pressure drop and tube-temperatures, corresponding to the overall heat transfer rate to each tube. The loop seal was operated under various conditions, including those typical for the boiler. Thus, the recirculation flux of solids through the loop seal, as well as the fluidization velocity in the seal, were varied. In addition, the fraction of the bottom area that is fluidized was varied. The overall flow behavior of the CFB loop with the scaled loop seal was found to be similar to that of the boiler. The temperature measurements showed that the heat transfer rate to the tubes in the bundle differed depending on operating conditions and on the position of the tube, both laterally and vertically. The recirculation flux could be maintained with a substantial decrease of the fluidization flow in the seal compared to the conditions corresponding to full load in the boiler. In addition, it was possible to significantly decrease the fraction of the bottom of the seal that was fluidized. However, if the area beneath the tube bundle is not fluidized, the heat transfer rate to the tubes decreased.

scholarly journals Free and Forced Convective Heat Transfer through a Nanofluid with Two Dimensions past Stretching Vertical Plate

2020 ◽  
Vol 7 (3) ◽  
Author(s):  
B. Sailaja ◽  
G. Srinivas ◽  
B.S. Babu
Keyword(s):  
Heat Transfer ◽  
Heat Source ◽  
Convective Heat Transfer ◽  
Forced Convection ◽  
Heat Transfer Rate ◽  
Convective Heat ◽  
Transfer Rate ◽  
Vertical Plate ◽  
Two Dimensions ◽  
Forced Convective Heat Transfer

The present study focus on both free and forced convective heat transfer through a nanofluid in two dimensions past stretching vertical plate. This free and forced convective heat transfer in Cu–water Nanofluid past permeable flat vertical semi-infinite plate was due to high conductivity and its occurrence. In this paper magnetic field and also heat source were considered. In graphs the effect on various parameters such as Reynolds number (Re) , solid volume fraction (φ), magnetic field parameter (M), inclination angle of the plate (γ ), heat source parameter (Qh), on linear velocity (U), vertical velocity (V) and temperature (θ) were exhibited. The profile of every governing parameter is displayed for natural as well as forced convection by considering the Ar >> 1 and Ar << 1 respectively. This rate of heat transfer in forced convection is more than equivalent in free convection. So these problems have several applications in engineering and petroleum industries such as electroplating, chemical processing of heavy metals and solar water heaters. Inertial force reducing the heat transfer rate in natural convection but the enhancement of Nu observed in forced convection. The composition of metal particles enhances the heat transfer rate in both convections, which emphasizes the nanofluid significance. Lorentz force is enhancing the heat transfer rate slightly. Heat source obviously increase the rate of heat transfer in both convections. The present paper aims to study the convective high temperature transfer of nanofluids into which viscosity proposed by Einstein and thermal conductivity proposed by Corcione were used.

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