EFFECT OF CONDENSATE FLOW RATE AND VAPOR VELOCITY ON CONDENSATE RETENTION FOR PIN-FIN TUBES

2019 ◽  
Vol 26 (6) ◽  
pp. 619-630
Author(s):  
Hassan Ali ◽  
Nasir Rafique ◽  
Amjad Hussain ◽  
Muazzam Ali ◽  
Haroon Farooq
Keyword(s):  
Flow Rate ◽  
Vapor Velocity ◽  
Pin Fin ◽  
Fin Tubes

scholarly journals Condensate retention as a function of condensate flow rate on horizontal enhanced pin-fin tubes

2019 ◽  
Vol 23 (6 Part B) ◽  
pp. 3887-3892 ◽  
Author(s):  
Hafiz Ali ◽  
Hassan Ali ◽  
Muhammad Abubaker ◽  
Ahmed Saieed ◽  
William Pao ◽  
...  
Keyword(s):  
Surface Tension ◽  
Ethylene Glycol ◽  
Flow Rate ◽  
Density Ratio ◽  
Test Tube ◽  
Pin Fin ◽  
Fin Tubes

The extent of condensate flooding as a function of condensate flow rate is measured on six horizontal pin-fin tubes (varying in circumferential pin-spacing) via simulated experimentation. Surface tension to density ratio is tested using three fluids namely water, ethylene glycol and R-141b. Results show that flooding was strongly effected by changing the condensate flow rate. An increase in flow rate caused a marginal decrease in flooding angle (an angle extracted from top of the test tube to the fully flooded flank). Similarly, circumferential pin-spacing also effected the retention angle and the effect goes on increasing by decreasing the surface tension to density ratio.

Effect of vapour velocity on condensate retention on horizontal pin-fin tubes

2014 ◽  
Vol 86 ◽  
pp. 1001-1009 ◽  
Author(s):  
Hafiz Muhammad Ali ◽  
Muhammad Abubaker
Keyword(s):  
Pin Fin ◽  
Fin Tubes

Lateral-Flow Effect on Endwall Heat Transfer and Pressure Drop in a Pin-Fin Trapezoidal Duct of Various Pin Shapes

2000 ◽  
Vol 123 (1) ◽  
pp. 133-139 ◽  
Author(s):  
Jenn-Jiang Hwang ◽  
Chau-Ching Lu
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Pressure Drop ◽  
Flow Rate ◽  
Lateral Flow ◽  
Transfer Enhancement ◽  
Pin Fin ◽  
Flow Reynolds Number ◽  
Outlet Flow ◽  
Flow Through

The effects of lateral-flow ejection 0<ε<1.0, pin shapes (square, diamond, and circular), and flow Reynolds number (6000<Re<40,000) on the endwall heat transfer and pressure drop for turbulent flow through a pin-fin trapezoidal duct are studied experimentally. A staggered pin array of five rows and five columns is inserted in the trapezoidal duct, with the same spacings between the pins in the streamwise and spanwise directions: Sx/d=Sy/d=2.5. Three different-shaped pins of length from 2.5<l/d<4.6 span the distance between two endwalls of the trapezoidal duct. Results reveal that the pin-fin trapezoidal duct with lateral-flow rate of ε=0.3-0.4 has a local minimum endwall-averaged Nusselt number and Euler number for all pin shapes investigated. The trapezoidal duct of lateral outlet flow only (ε=1.0) has the highest endwall heat transfer and pressure drop. Moreover, the square pin results in a better heat transfer enhancement than the diamond pin, and subsequently than the circular pin. Finally, taking account of the lateral-flow rate and the flow Reynolds number, the work develops correlations of the endwall-averaged heat transfer with three different pin shapes.

Forced-Convection Condensation of Ethylene Glycol on Integral-Fin Tubes

2004 ◽  
Author(s):  
Satesh Namasivayam ◽  
Adrian Briggs
Keyword(s):  
Ethylene Glycol ◽  
Forced Convection ◽  
Experimental Studies ◽  
Heat Fluxes ◽  
Slight Reduction ◽  
Enhancement Ratio ◽  
Vapor Velocity ◽  
Wide Range ◽  
Plain Tube ◽  
Fin Tubes

This paper reports new experimental data for forced-convection condensation of ethylene glycol on a set of five single, copper, integral-fin tubes. The five tubes had fin root diameter of 12.7 mm, fin height and thickness of 1.6 mm and 0.25 mm respectively. Fin spacings were 0.25, 0.5, 1.0, 1.5 and 2.0 mm. A plain tube of outside diameter 12.7 mm was also tested. The tests, which were performed at near constant pressure of approximately 15 kPa, covered vapor velocities between 10 and 22 m/s and a wide range of heat fluxes. The best performing tube was that with a fin spacing of 0.5 mm, which had an enhancement ratio (compared to the plain tube at the same vapor-side temperature difference and vapor velocity) of 2.5 at the lowest vapor velocity tested, increasing to 2.7 at the highest. The increase in enhancement ratio with increasing vapor velocity, which is the opposite trend to that found in most earlier experimental studies, was thought to be due to a slight reduction in condensate flooding between the fins due to increased vapor shear.

Lateral-Flow Effect on Endwall Heat Transfer and Pressure Drop in a Pin-Fin Trapezoidal Duct of Various Pin Shapes

2000 ◽  
Author(s):  
Jenn-Jiang Hwang ◽  
Chau-Ching Lu
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Pressure Drop ◽  
Flow Rate ◽  
Lateral Flow ◽  
Transfer Enhancement ◽  
Pin Fin ◽  
Flow Reynolds Number ◽  
Outlet Flow ◽  
Flow Through

Effects of the lateral-flow ejection (0 ≦ ε ≦ 1.0), pin shapes (square, diamond and circular) and flow Reynolds number (6,000 ≦ Re ≦ 40,000) on the endwall heat transfer and pressure drop for turbulent flow through a pin-fin trapezoidal duct are studied experimentally. The trapezoidal duct are inserted with a staggered pin array of five rows and five columns, with the same spacings between the pins in streamwise and spanwise directions of Sx/d = Sy/d = 2.5. Three different-shaped pins of length from 2.5 < l/d < 4.6 span the distance between two endwalls of the trapezoidal duct. Results reveal that the pin-fin trapezoidal duct with a lateral-flow rate of ε = 0.3–0.4 has a local minimum endwall-averaged Nusselt number and Euler number for all pin shapes investigated. The trapezoidal duct of lateral outlet flow only (ε = 1.0) has the highest endwall heat transfer and pressure drop. Moreover, the square pin performs a better heat transfer enhancement than the diamond pin, and subsequently than the circular pin. Finally, taking account of the lateral-flow rate and the flow Reynolds number develops correlations of the endwall-averaged heat transfer for three different pin shapes.

Numerical Analysis of Flat Plate Solar Air Heater Integrated With an Array of Pin Fins on Absorber Plate for Enhancement in Thermal Performance

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
M. S. Manjunath ◽  
K. Vasudeva Karanth ◽  
N. Yagnesh Sharma
Keyword(s):  
Numerical Analysis ◽  
Flat Plate ◽  
Flow Rate ◽  
Solar Air Heater ◽  
Absorber Plate ◽  
Pin Fin ◽  
Pin Fins ◽  
Effective Efficiency ◽  
Pin Fin Array ◽  
Lower Flow Rate

This paper presents a three-dimensional numerical analysis of a flat plate solar air heater in the presence of a pin fin array using the computational fluid dynamics (CFD) software tool ansys fluent 16.2. The effect of geometric parameters of pin fins as well as the flow Reynolds number (4000–24,000) on the effective efficiency is evaluated. The longitudinal pitch (PL) of pin fin array is varied as 30 mm, 40 mm, and 50 mm and the diameter (Dw) is varied as 1.0 mm, 1.6 mm, and 2.2 mm. The results show that the presence of pin fins generate considerable enhancement in fluid turbulence as well as heat transfer area to a maximum extent of about 53.8%. The maximum average increase in instantaneous thermal efficiency is found to be about 14.2% higher as compared with the base model for the fin diameter of 2.2 mm and a longitudinal pitch value of 30 mm. In terms of effective efficiency, the pin fin array exhibits significant enhancement, especially at lower flow rate conditions. Finally, the effective efficiency of the pin fin array is compared with the previous work of authors involving spherical turbulators and sinewave corrugations on the absorber plate. The results show that the pin fin array exhibits a relatively superior effective efficiency to a maximum extent of about 73% for lower flow rate conditions.

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