Heat Exchanger Networks Targeting and Design with Unequal Heat Transfer Coefficient Regarding Allowable Pressure Drop of Streams

2006 ◽  
Vol 27 (9) ◽  
pp. 36-43 ◽  
Author(s):  
M. H. Panjeh Shahi ◽  
A. Khoshgard
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Swanand Gaikwad ◽  
Ashish Parmar

AbstractHeat exchangers possess a significant role in energy transmission and energy generation in most industries. In this work, a three-dimensional simulation has been carried out of a shell and tube heat exchanger (STHX) consisting of segmental baffles. The investigation involves using the commercial code of ANSYS CFX, which incorporates the modeling, meshing, and usage of the Finite Element Method to yield numerical results. Much work is available in the literature regarding the effect of baffle cut and baffle spacing as two different entities, but some uncertainty pertains when we discuss the combination of these two parameters. This study aims to find an appropriate mix of baffle cut and baffle spacing for the efficient functioning of a shell and tube heat exchanger. Two parameters are tested: the baffle cuts at 30, 35, 40% of the shell-inside diameter, and the baffle spacing’s to fit 6,8,10 baffles within the heat exchanger. The numerical results showed the role of the studied parameters on the shell side heat transfer coefficient and the pressure drop in the shell and tube heat exchanger. The investigation shows an increase in the shell side heat transfer coefficient of 13.13% when going from 6 to 8 baffle configuration and a 23.10% acclivity for the change of six baffles to 10, for a specific baffle cut. Evidence also shows a rise in the pressure drop with an increase in the baffle spacing from the ranges of 44–46.79%, which can be controlled by managing the baffle cut provided.


2013 ◽  
Vol 832 ◽  
pp. 160-165 ◽  
Author(s):  
Mohammad Alam Khairul ◽  
Rahman Saidur ◽  
Altab Hossain ◽  
Mohammad Abdul Alim ◽  
Islam Mohammed Mahbubul

Helically coiled heat exchangers are globally used in various industrial applications for their high heat transfer performance and compact size. Nanofluids can provide excellent thermal performance of this type of heat exchangers. In the present study, the effect of different nanofluids on the heat transfer performance in a helically coiled heat exchanger is examined. Four different types of nanofluids CuO/water, Al2O3/water, SiO2/water, and ZnO/water with volume fractions 1 vol.% to 4 vol.% was used throughout this analysis and volume flow rate was remained constant at 3 LPM. Results show that the heat transfer coefficient is high for higher particle volume concentration of CuO/water, Al2O3/water and ZnO/water nanofluids, while the values of the friction factor and pressure drop significantly increase with the increase of nanoparticle volume concentration. On the contrary, low heat transfer coefficient was found in higher concentration of SiO2/water nanofluids. The highest enhancement of heat transfer coefficient and lowest friction factor occurred for CuO/water nanofluids among the four nanofluids. However, highest friction factor and lowest heat transfer coefficient were found for SiO2/water nanofluids. The results reveal that, CuO/water nanofluids indicate significant heat transfer performance for helically coiled heat exchanger systems though this nanofluids exhibits higher pressure drop.


2013 ◽  
Vol 655-657 ◽  
pp. 461-464 ◽  
Author(s):  
Su Fang Song

The three-dimensional model of heat exchangers with continuous helical baffles was built. The fluid flow dynamics and heat transfer of shell side in the helical baffled heat exchanger were simulated and calculated. The velocity, pressure and temperature distributions were achieved. The simulation shows that with the same baffle pitch, shell-side heat transfer coefficient increased by 25% and the pressure drop decreases by 18% in helical baffled heat exchanger compared with segmental helical baffles. With the analyzing of the flow and heat transfer in heat exchanger in 5 different inclination angles from 11°to 21°, it can be found that both shell side heat transfer coefficient and pressure drop will reduce respectively by 86% and 52% with the increases 11°to 21°of the inclination angles. Numerical simulation provided reliable theoretical reference for further engineering research of heat exchanger with helical baffles.


1968 ◽  
Vol 32 (11) ◽  
pp. 1127-1132,a1 ◽  
Author(s):  
Katsuto Okada ◽  
Minobu Ono ◽  
Toshio Tomimum ◽  
Hirotaka Konno ◽  
Shigemori Ohtani

Author(s):  
S. V. Sridhar ◽  
R. Karuppasamy ◽  
G. D. Sivakumar

Abstract In this investigation, the performance of the shell and tube heat exchanger operated with tin nanoparticles-water (SnO2-W) and silver nanoparticles-water (Ag-W) nanofluids was experimentally analyzed. SnO2-W and Ag-W nanofluids were prepared without any surface medication of nanoparticles. The effects of volume concentrations of nanoparticles on thermal conductivity, viscosity, heat transfer coefficient, fiction factor, Nusselt number, and pressure drop were analyzed. The results showed that thermal conductivity of nanofluids increased by 29% and 39% while adding 0.1 wt% of SnO2 and Ag nanoparticles, respectively, due to the unique intrinsic property of the nanoparticles. Further, the convective heat transfer coefficient was enhanced because of improvement of thermal conductivity of the two phase mixture and friction factor increased due to the increases of viscosity and density of nanofluids. Moreover, Ag nanofluid showed superior pressure drop compared to SnO2 nanofluid owing to the improvement of thermophysical properties of nanofluid.


Author(s):  
Rajinder Singh ◽  
Surendra Singh Kachhwaha

The present study reports the experimental validation of thermohydraulic modeling for prediction of pressure drop and heat transfer coefficient. Experiments were performed on plate heat exchanger using chilled water and ice slurry as secondary fluids. Propylene glycol (PG) and mono-ethylene glycol (MEG) are used as depressants (10%, 20%, 30%, and 40% concentration) in ice slurry formation. The results show that thermohydraulic modeling predicts the pressure drop and overall heat transfer coefficient for water to water and water to ice slurry within the discrepancy limit of ±15%.


Author(s):  
M. H. Saidi ◽  
A. A. Mozafari ◽  
A. R. Esmaeili Sany ◽  
J. Neyestani

In this Study, radiator performance for passenger car has been studied experimentally in wide range of operating conditions. Experimental prediction of Nusselt number and heat transfer coefficient for coolant in radiator tubes are also performed with ε–NTU method. The total effectiveness coefficient of radiator and heat transfer coefficient in air side is calculated via try and error method considering experimental data. The Colburn factor and pressure drop are also estimated for this heat exchanger. Examples of application demonstrate the practical usefulness of this method to provide empirical data which can be used during the design stage.


Author(s):  
Suriyan Laohalertdecha ◽  
Somchai Wongwises

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.


Author(s):  
Shui Ji ◽  
Wenjing Du ◽  
Lin Cheng

Since its appearance in the 80’s of the 20th century, the heat exchanger with helical baffles (HEHBs) has attracted lots of attention. Benefiting from its relatively simple manufacture procedure and low cost, the heat exchanger with overlapped helical baffles receives much concern. However, there are few reports on the influence of the specific overlap size of helical baffles on the shell-side heat transfer performance and fluid friction property. In this paper, numerical investigation on this open issue is carried out by means of numerical method. The emphasis is laid on the relationship between the overlap size of helical baffles and the shell-side performance. Baffles with the shape of a quarter-ellipse are simulated and the heat-transfer oil is selected as the working fluid. Results show that in the condition of same helix angles and same flow rates, 10% increase of the specific overlap size brings an increase of 23–42% on the pressure drop and an increase of 2–8% on the convection heat transfer coefficient; hence the corresponding heat transfer coefficient pre unit pressure drop is decreased by 11–22%. Compared with the continuously overlap configuration, the axially staggered overlap helical baffles can improve the comprehensive performance of HEHBs on the condition of an identical helical pitch, and hence it is favorable for the situation with strict constrain on pressure drop.


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