A Novel Gas-Water Heat Exchanger With Minichannels

2008 ◽  
Author(s):  
Yang Chen ◽  
Per Lundqvist ◽  
Bjo¨rn Palm

In the current study, a novel gas water heat exchanger with minichannels is designed, built and tested. The heat exchanger is mainly composed of a number of concentric ring shaped plates, which are made up of several heat exchanger tubes. The ring shaped plates are arranged in parallel and placed in a shell. The heat exchanger is designed as a counter current heat exchanger with laminar flow on the heat exchanger’s shell-side (gas side) and therefore has a very low pressure drop on the shell side. The heat exchanger was tested with water and hot air on its tube-side and shell-side respectively. All the necessary parameters like inlet and outlet temperatures on tube-side and shell-side as well as the pressure drop, flow rate of fluids, etc. were measured. Different existing correlations were used to calculate the overall heat transfer coefficient and the results were compared with the measured value. The measured results show that the new designed heat exchanger can achieve a good heat transfer performance and also maintain a low pressure drop on shell-side (gas side).

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 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.


2012 ◽  
Vol 560-561 ◽  
pp. 156-160
Author(s):  
Lin Ping Lu ◽  
Liang Ying

The experiments on heat transfer coefficient, pressure drop and thermal stress were done to heat exchangers with corrugated tubes and staight tubes. By analyising and comparing the heat transfer coeffient, pressure drop in tube side and shell side and axial force and stress, some conclusions can be conducted that the corrugated tube heat exchanger has better heat transfer coeffient, higher pressure drop and much lower stress caused by temperatur difference, also, it has obvious advantages under the circumstance of low Reynolds number and high temperature difference.


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.


Author(s):  
Guidong Chen ◽  
Jing Xu ◽  
Ming Zen ◽  
Qiuwang Wang

In order to improve heat transfer performance of conventional segmental baffled shell-and-tube heat exchangers (STHXs), the shell-and-tube heat exchanger with combined helical baffles (CMH-STHX) were invented. In the present study, the CMH-STHX is compared with three other STHXs which were set up with continuous helical baffles (CH-STHX), discontinuous helical baffles (DCH-STHX) and segmental baffles (SG-STHX), by Computational Fluid Dynamics method. The numerical results show that, for the same mass flow rate at the shell side, the overall pressure drop of the CMH-STHX is about 50% and 40% lower than that of SG-STHX and CH-STHX. The heat transfer coefficient of the CMH-STHX is between those of CH-STHX and DCH-STHX and it is 6.3% lower than that of SG-STHX. The heat transfer coefficient under unit pressure drop h/Δp is introduced to evaluate the comprehensive performance of STHXs. The h/Δp of the CMH-STHX is 7.5%, 6.5% and 87.4% higher on average than those of the CH-SHTX, DCH-STHX and SG-STHX. Furthermore, the total heat transfer rate of CMH-STHX is about 25% higher than that of SG-STHX for the same total pressure drop of shell side. Supported by these results, the new heat exchanger (CMH-STHX) may be used to replace the conventional shell-and-tube heat exchanger in industrial applications.


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