Heat Transfer Characteristics of an Array of Impinging Gaseous Slot Jets

2011 ◽  
Vol 396-398 ◽  
pp. 2234-2239
Author(s):  
Zu Ling Liu ◽  
Cheng Bo Wu ◽  
Xian Jun Wang ◽  
Zheng Rong Zhang
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Nozzle Exit ◽  
Convective Heat Transfer Coefficient ◽  
Heat Transfer Characteristics ◽  
Forced Convective Heat Transfer

A comprehensive experiment was conducted for heat transfer characteristics for an array of impinging gaseous slot jets to a flat plate with strong turbulence (nozzle exit Reynolds number Re=22500~64700).Find that turbulence intensity of flow has an important influence on local forced convective heat transfer coefficient. Meanwhile, the nozzle-to-plate spacing and nozzle exit Reynolds number Re would affect the mean forced convective heat transfer coefficient of the slot jets. And heat transfer efficiency of slot jets has been set to show the relation between ability of the jets and energy consumption of gas supply.

Experimental Convective Heat Transfer With Nanofluids

2008 ◽  
Author(s):  
S. Kabelac ◽  
K. B. Anoop
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Turbulent Regime ◽  
Heat Transfer Characteristics ◽  
Forced Convective Heat Transfer ◽  
Transfer Characteristics

Nanofluids are colloidal suspensions with nano-sized particles (<100nm) dispersed in a base fluid. From literature it is seen that these fluids exhibit better heat transfer characteristics. In our present work, thermal conductivity and the forced convective heat transfer coefficient of an alumina-water nanofluid is investigated. Thermal conductivity is measured by a steady state method using a Guarded Hot Plate apparatus customized for liquids. Forced convective heat transfer characteristics are evaluated with help of a test loop under constant heat flux condition. Controlled experiments under turbulent flow regime are carried out using two particle concentrations (0.5vol% and 1vol %). Experimental results show that, thermal conductivity of nanofluids increases with concentration, but the heat transfer coefficient in the turbulent regime does not exhibit any remarkable increase above measurement uncertainty.

Gas Solids Suspension Convective Heat Transfer at a Reynolds Number of 130,000

1968 ◽  
Vol 90 (4) ◽  
pp. 464-468 ◽  
Author(s):  
R. Briller ◽  
R. L. Peskin
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Particle Temperature ◽  
Convective Heat Transfer Coefficient ◽  
Loading Ratio ◽  
High Reynolds

An experiment was performed to determine the convective heat-transfer coefficient to heated and cooled gas solids suspensions at a Reynolds number of 130,000. Measurements of the heat transfer were performed by traversing the stream at various locations along the pipe with specially designed probes which measured air and particle temperature locally. The results showed that for a high Reynolds number, the heat-transfer coefficient for the suspension appears to be equal to that of the pure gas at the same Reynolds number, and independent of solids loading ratio, heating or cooling, and particle size (between 0.0011 and 0.0058 in. dia).

Heat-Transfer Characteristics and Design Optimization for a Small-Sized Plate-Fin Heat Sink Array

2007 ◽  
Vol 129 (4) ◽  
pp. 518-521 ◽  
Author(s):  
Gaowei Xu ◽  
Yingjun Cheng ◽  
Le Luo
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Heat Sink ◽  
Convective Heat Transfer Coefficient ◽  
Heat Sinks ◽  
Heat Transfer Characteristics ◽  
Fin Thickness

The heat-transfer characteristics of 128 small-sized plate-fin heat sinks in a supercomputer chassis are investigated with CFD simulation. The V-shaped curves of the chip temperature versus fin pitch and fin thickness are derived and a thermal resistance model is built to explore the profile and obtain the convective heat-transfer coefficient of the heat sinks. It turns out that the V-shaped profile arises from the joint action of the thermal conduction and convection of heat sink, which can be attributed to the intricacy of the dependencies of thermal resistances on either fin pitch or thickness. It can be further concluded that Biot criterion is applicable to estimate the Biot number of large-scale plate-fin heat sink but not applicable for the small-sized one. The convective heat-transfer coefficient is a complicated function of fin pitch and fin thickness. The empirical formulas of heat transfer are obtained and the fin pitch and fin thickness are optimized.

scholarly journals Investigation on Heat Transfer and Pressure Drop Performance Utilizing GNP-based Colloidal Suspension Flow in Finned Conduit

2021 ◽  
Vol 945 (1) ◽  
pp. 012056
Author(s):  
Yanru Wang ◽  
Cheen Sean Oon ◽  
Manh-Vu Tran ◽  
Joshua Yap Kee An
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Colloidal Suspension ◽  
Convective Heat Transfer Coefficient ◽  
Constant Heat Flux

Abstract Heat exchangers have been widely used in various engineering applications. It is important to develop a highly efficient heat transfer equipment to reduce carbon footprint. In the current research, the effect of 0.025wt% CGNP/water nanofluid on convective heat transfer and pressure drop performance is investigated numerically in finned conduits with circular and square geometry. ANSYS FLUENT is used to analyze the turbulent flow inside the conduits with Reynolds number ranging from 7360 to 28011 and constant heat flux 12254.90W/m2 and 9615.38W/m2 in circular and square geometry, respectively. Only 1/8 of the pipe was constructed in the simulation as the geometry is symmetrical. The numbers of mesh elements are 465488 and 469144 for circular and square conduits. SST k-omega viscous model, SIMPLEC scheme and second-order upwind solvers are used in this model, where SST k-omega viscous model is good at solving turbulence parameters in the near wall boundary regions. It is found that the use of CGNP/water nanofluid can increase convective heat transfer coefficient without increasing pressure drop compared with water. Besides, the circular pipe shows higher heat transfer enhancement compared with square pipe. Furthermore, the increase in Reynolds number enhances the Nusselt number and heat transfer coefficient in both circular and square geometries. It is recommended that circular finned pipe and CGNP/water colloidal suspension could be applied in low turbulence flow setting heat exchanger.

Experimental Investigation on Heat Transfer Characteristics of CO2-Based Foam Fracturing Fluid

2013 ◽  
Vol 805-806 ◽  
pp. 1278-1282
Author(s):  
Ze Feng Jing ◽  
Shu Zhong Wang ◽  
Xiang Rong Luo
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Shear Rate ◽  
Transfer Coefficient ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Convective Heat Transfer Coefficient ◽  
Heat Transfer Characteristics ◽  
Fracturing Fluid ◽  
Transfer Characteristics

Heat transfer characteristics of the CO2-based foam fracturing fluid were investigated on the large-scale test loop of foam fracturing fluid. The relationship between thermal conductivity coefficient and shear rate was introduced into the expression of the convective heat transfer coefficient. Thus the expression of the convective heat transfer coefficient of power-law fluid was revised. The results show that the convective heat transfer coefficient of the fracturing fluid increases with the increase of the pressure, the foam quality and the shear rate. The convective heat transfer coefficient of the foam fracturing fluid calculated by the revised calculation formula is highly consistent with the experimental data at low pressure. The deviation is bigger at high pressure, but still within 20%.

Sign in / Sign up

Export Citation Format

Share Document