Experimental study on condensation heat transfer and pressure drop in horizontal smooth tube for R1234ze(E), R32 and R410A

2012 ◽  
Vol 35 (4) ◽  
pp. 927-938 ◽  
Author(s):  
Md. Anowar Hossain ◽  
Yoji Onaka ◽  
Akio Miyara
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Pressure Drop ◽  
Condensation Heat Transfer ◽  
Smooth Tube

Effects of Pitch and Depth on the Condensation Heat Transfer of R-134a Flowing Through Corrugated Tubes

2011 ◽  
Author(s):  
Suriyan Laohalertdecha ◽  
Somchai Wongwises
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Condensation Heat Transfer ◽  
Smooth Tube ◽  
Maximum Heat ◽  
Frictional Pressure Drop ◽  
R 134A

The effects of pitch and depth on the condensation heat transfer of R-134a flowing inside corrugated tubes are experimentally investigated. The test section is a horizontal tube-in-tube heat exchanger. The refrigerant flows in the inner tube and the water flows in the annulus. The length of heat exchanger is 2 m. A smooth tube and corrugated tubes having inner diameters of 8.7 mm are used as an inner tube. The corrugation pitches used in this study are 5.08, 6.35, and 8.46 mm. Similarly, the corrugation depths are 1, 1.25, and 1.5 mm. The effects of corrugation pitch and depth on tube wall temperature, heat transfer coefficient and frictional pressure drop are discussed. The results illustrate that the maximum heat transfer coefficient and frictional pressure drop obtained from the corrugated tube are up to 50% and 70% higher than those obtained from the smooth tube, respectively.

Experimental Study on Heat Transfer and Fluid Flow in Vertical Rifled

2012 ◽  
Vol 505 ◽  
pp. 524-533 ◽  
Author(s):  
Abdulati Muftah Mohamed Ibrahim ◽  
Bashir Rahuma Elhub ◽  
H. Abas A. Wahab
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Fluid Flow ◽  
Pressure Drop ◽  
Flow Rate ◽  
Smooth Tube ◽  
Enhancement Effect ◽  
Outer Diameter ◽  
Flow Monitoring ◽  
Inner Diameter

In this paper, heat transfer and fluid flow monitoring experiments for pressure drop and efficiency were performed to investigate the fluid flow characteristics of rifled tubes in comparison with a smooth tube. The rifled tube has an outer diameter of 25mm, maximum inner diameter of 18.8 mm; minimum inner diameter of 17.50mm, rib height of 0.6835, rib width of 9.25, helix angles 60 o and the number of starts is four. The smooth tube has an outer diameter of 26.7mm and an inner diameter of 18.88 mm, with a wall thickness of 3.91mm. The experiments were conducted on a vertical orientation of the steel tubes (rifled and smooth) under varying flow rate of 15, 30, 40, 50, 60 and 70. The fluid used is 131.64 litres of water and the initial temperature is 25oC. The fluid is raised to an average temperature of 33oC during the experimental study. During the experiment, it was found that at 360 mins for the smooth tube, an increase in flow rate does not affect the time for the fluid (water) to attain a temperature of 33oC. For the rifled tube, as the flow rate increases, the time for the fluid (water) to attain a temperature of 33oC also increases. This is as a result of the effect of ribbing the tube. The time taken to attain the optimum temperature of 33oC is shorter using the rifled tube than the smooth tube. The rifled tube has heat transfer efficiency higher than the smooth tube. The pressure drop and the energy consumed by using the rifled tube were also found to be less than that of the smooth tube. The pressure drop increase factor was found to be 0.85 in the spirally rifled tube as compared to the smooth tube at the different flow rates. The enhancement effect of ribbing the tube is apparent.

scholarly journals Experimental Study on R245fa Condensation Heat Transfer in Horizontal Smooth Tube and Enhanced Tube

2017 ◽  
Vol 142 ◽  
pp. 4169-4175 ◽  
Author(s):  
Shengchun Liu ◽  
Ming Song ◽  
Baomin Dai ◽  
Yuan Tian ◽  
Mengjie Song ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Condensation Heat Transfer ◽  
Smooth Tube ◽  
Enhanced Tube

A Experimental Study of Condensation Heat Transfer and Pressure Drop in a Single High Aspect Ratio Micro-Channel for Refrigerant R134a

2006 ◽  
Author(s):  
Sourav Chowdhury ◽  
Ebrahim Al-Hajri ◽  
Serguei Dessiatoun ◽  
Amir Shooshtari ◽  
Michael Ohadi
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Pressure Drop ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Small Diameter ◽  
Hydraulic Diameter ◽  
Condensation Heat Transfer ◽  
Small Scale ◽  
Measurement Instruments

Only recently, experimental data is available in open literature in condensation of various refrigerants in small hydraulic diameter microchannels. The phenomenon of two-phase flow and heat transfer mechanism in small diameter microchannels (< 1 mm) may be different than that in conventional tube sizes due to increasing dominance of several influencing parameters like surface tension, viscosity etc. This paper presents an on-going experimental study of condensation heat transfer and pressure drop of refrigerant R134a is a single high aspect ratio rectangular microchannel of hydraulic diameter 0.7 mm and aspect ratio 7:1. This data will help explore the condensation phenomenon in microchannels that is necessary in the design and development of small-scale heat exchangers and other compact cooling systems. The inlet vapor qualities between 20% and 80% and mass fluxes of 130 and 200 kg/m2s have been studied at present. The microchannel outlet conditions are maintained at close to thermodynamic saturated liquid state through a careful experimental procedure. A unique process for fabrication of the microchannel involving milling and electroplating steps has been adopted to maintain the channel geometry close to design values. Measurement instruments are well-calibrated to ensure low system energy balance error, uncertainty and good repeatability of test data. The trends of data recorded are comparable to that found in recent literature on similar dimension tubes.

scholarly journals Correlation for Condensation Heat Transfer in a 4.0 mm Smooth Tube and Relationship with R1234ze(E), R404A, and R290

2018 ◽  
Vol 8 (11) ◽  
pp. 2267 ◽  
Author(s):  
Norihiro Inoue ◽  
Masataka Hirose ◽  
Daisuke Jige ◽  
Junya Ichinose
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Small Diameter ◽  
Saturation Temperature ◽  
Condensation Heat Transfer ◽  
Smooth Tube ◽  
General Correlation ◽  
Condensation Heat Transfer Coefficient

In this study, the condensation heat transfer coefficient and pressure drop characteristics of a 4 mm outside diameter smooth tube, using R32, R152a, R410A, and R1234ze(E) refrigerants, were examined. Condensation heat transfer coefficients and pressure drops were measured at a saturation temperature of 35 °C, in the region of mass velocities from 100 to 400 kg m−2s−1. The frictional pressure drop, and the condensation heat transfer from the new measurements, using R1234ze(E) as a refrigerant, were compared with those of R32, R152a, and R410A, in the smooth tube. Experimental values of condensation heat transfer coefficient of smooth tube were also compared to the predicted values obtained using the previously established correlations. The previous correlation from Cavallini et al., for the condensation heat transfer coefficient of small-diameter smooth tube, was estimated to be within ±30%. However, the general correlation, which can be easily predicted, for condensation heat transfer inside small-diameter smooth tubes, was suggested, and the relationship of the general correlation was compared with data for R1234ze(E) obtained by us, and R404A and R290 obtained by other researchers.

An Experimental Study of R134a Condensation Heat Transfer in Horizontal Smooth and Enhanced Tubes

2020 ◽  
Author(s):  
Yu Guo ◽  
Zong-bao Gu ◽  
Zahid Ayub ◽  
Wei Li ◽  
Xiang Ma ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Mass Flux ◽  
Surface Structures ◽  
Condensation Heat Transfer ◽  
Smooth Tube ◽  
Outer Diameter ◽  
Enhanced Tubes

Abstract In this paper, the condensation heat transfer characteristics of R134a inside enhanced tubes using two type of surface structures with different materials was investigated, which were then compared with plain tubes under the same test conditions. The enhanced tubes were: 1EHTa tube with dimpled and petal arrays structure and 1EHTb tube with protrusion and similar petal arrays structure. The experiment was conducted for a mass flux ranging from 100 to 200 kg m−2 s−1 with saturation temperature of 318 K. The inlet and outlet vapor qualities were fixed at 0.8 and 0.2, respectively. The test tubes had the same outer diameter of 12.7 mm. Results showed that the dimpled and protruded surface tubes enhanced the convection condensation heat transfer and the heat transfer coefficient was 1.4 to 1.6 times higher than that of the smooth tube. Heat transfer enhancement of the 1EHTa and 1EHTb tube was mainly due to the complex roughness surface structures that created swirling and increased the interface turbulence. Enhanced tubes exhibited higher performance factors compared to the smooth tube. The average performance factor was 1.3–1.5. As the flow rate increases, there is no significant increase in the condensation heat transfer coefficient. The pressure drop penalty increased with mass flux. Compared with smooth tube, the pressure drop penalty of enhanced tube was larger.

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