Experimental Investigation of Heat Transfer Rate and Pressure Drop through Angled Compact Heat Exchangers Relative to the Incoming Airflow

2014 ◽  
Vol 7 (2) ◽  
pp. 448-457 ◽  
Author(s):  
Lisa Henriksson ◽  
Erik Dahl ◽  
Peter Gullberg ◽  
Arnaud Contet ◽  
Thomas Skare ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Pressure Drop ◽  
Heat Transfer Rate ◽  
Heat Exchangers ◽  
Transfer Rate ◽  
Compact Heat Exchangers

Pressure Drop and Heat Transfer Characteristics of Louvered Fin Heat Exchangers

2013 ◽  
Vol 465-466 ◽  
pp. 500-504 ◽  
Author(s):  
Shahrin Hisham Amirnordin ◽  
Hissein Didane Djamal ◽  
Mohd Norani Mansor ◽  
Amir Khalid ◽  
Md Seri Suzairin ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Transfer Rate ◽  
Heat Exchangers ◽  
Transfer Rate ◽  
Three Dimensional ◽  
Considerable Effect ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Louvered Fin

This paper presents the effect of the changes in fin geometry on pressure drop and heat transfer characteristics of louvered fin heat exchanger numerically. Three dimensional simulation using ANSYS Fluent have been conducted for six different configurations at Reynolds number ranging from 200 to 1000 based on louver pitch. The performance of this system has been evaluated by calculating pressure drop and heat transfer coefficient. The result shows that, the fin pitch and the louver pitch have a very considerable effect on pressure drop as well as heat transfer rate. It is observed that increasing the fin pitch will relatively result in an increase in heat transfer rate but at the same time, the pressure drop will decrease. On the other hand, low pressure drop and low heat transfer rate will be obtained when the louver pitch is increased. Final result shows a good agreement between experimental and numerical results of the louvered fin which is about 12%. This indicates the capability of louvered fin in enhancing the performance of heat exchangers.

scholarly journals Heat Transfer Enhancement by Perforated and Louvred Fin Heat Exchangers

Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 400
Author(s):  
Miftah Altwieb ◽  
Rakesh Mishra ◽  
Aliyu M. Aliyu ◽  
Krzysztof J. Kubiak
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Transfer Rate ◽  
Heat Exchangers ◽  
Transfer Rate ◽  
Reynolds Numbers ◽  
Transfer Enhancement ◽  
Flow Rates ◽  
Pressure Drops ◽  
Fin Design

Multi-tube multi-fin heat exchangers are extensively used in various industries. In the current work, detailed experimental investigations were carried out to establish the flow/heat transfer characteristics in three distinct heat exchanger geometries. A novel perforated plain fin design was developed, and its performance was evaluated against standard plain and louvred fins designs. Experimental setups were designed, and the tests were carefully carried out which enabled quantification of the heat transfer and pressure drop characteristics. In the experiments the average velocity of air was varied in the range of 0.7 m/s to 4 m/s corresponding to Reynolds numbers of 600 to 2650. The water side flow rates in the tubes were kept at 0.12, 0.18, 0.24, 0.3, and 0.36 m3/h corresponding to Reynolds numbers between 6000 and 30,000. It was found that the louvred fins produced the highest heat transfer rate due to the availability of higher surface area, but it also produced the highest pressure drops. Conversely, while the new perforated design produced a slightly higher pressure drop than the plain fin design, it gave a higher value of heat transfer rate than the plain fin especially at the lower liquid flow rates. Specifically, the louvred fin gave consistently high pressure drops, up to 3 to 4 times more than the plain and perforated models at 4 m/s air flow, however, the heat transfer enhancement was only about 11% and 13% over the perforated and plain fin models, respectively. The mean heat transfer rate and pressure drops were used to calculate the Colburn and Fanning friction factors. Two novel semiempirical relationships were derived for the heat exchanger’s Fanning and Colburn factors as functions of the non-dimensional fin surface area and the Reynolds number. It was demonstrated that the Colburn and Fanning factors were predicted by the new correlations to within ±15% of the experiments.

Comparison of Additively Manufactured Louvered Plate-Fin Heat Exchangers

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Michael Bichnevicius ◽  
David Saltzman ◽  
Stephen Lynch
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
Pressure Drop ◽  
Heat Transfer Rate ◽  
Heat Exchangers ◽  
Transfer Rate ◽  
Print Quality ◽  
Side Pressure ◽  
Oil Cooler ◽  
Fin Thickness

Abstract Additive manufacturing (AM) enables improved heat exchanger (HX) designs where performance is based on the achievable geometry. However, consequences of the AM process that affect HX performance such as increased surface roughness, dimensional tolerance issues, and defects like cracks may vary among identically designed AM parts due to AM machine settings. This paper experimentally compares the thermal and hydraulic performance of three AM HXs built using a traditionally manufactured, stamped aluminum oil cooler design. The AM HXs exhibited significantly higher air-side pressure drop and higher heat transfer rate than the traditional HX in large part due to increased AM surface roughness. Among AM HXs, one AM HX had notably higher heat transfer rate and air-side pressure drop due to poor print quality on the thin air-side fin features. The fin thickness among AM HXs also varied by about 15%, and there were only slight differences in surface roughness. This study indicates that functional HXs built using AM vary in performance even when the same digital model is used to print them and that AM HXs as a group can perform considerably differently than their traditional counterparts.

Numerical Simulation of Manifold Microchannel Heat Exchanger

2016 ◽  
Author(s):  
Muhammad Ansab Ali ◽  
Tariq S. Khan ◽  
Ebrahim Al Hajri
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Heat Transfer Rate ◽  
Heat Exchangers ◽  
Transfer Rate ◽  
Water Mixture ◽  
Microchannel Heat Exchanger ◽  
Compact Size

The quest to achieve higher heat transfer rate, smaller size and minimum pressure drop is a main area of focus in the design of heat exchangers. Plate heat exchangers are one of viable candidates to deliver higher heat duties but still have a drawback of higher pressure drop due to long restricted flow path. Motivated by demand of miniaturization and cost reduction, a novel design of tubular microchannel heat exchanger for single phase flow employing ammonia water mixture is proposed. Numerical simulation of unit fluid domain is conducted in ANSYS Fluent. Parametric study of the different flow geometries is evaluated in terms of Nusselt number and pressure drop. The salient features of the design include ultra-compact size with higher heat transfer rate and acceptable pressure drop.

scholarly journals HEAT TRANSFER ENHANCEMENT AND PRESSURE DROP FOR FIN-AND-TUBE COMPACT HEAT EXCHANGERS WITH DELTA WINGLET-TYPE VORTEX GENERATORS

2018 ◽  
Vol 16 (2) ◽  
pp. 233 ◽  
Author(s):  
Seyed Alireza Ghazanfari ◽  
Malan Abdul Wahid
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Rate ◽  
Heat Exchangers ◽  
Pressure Loss ◽  
Transfer Rate ◽  
Vortex Generators ◽  
Compact Heat Exchanger ◽  
Compact Heat Exchangers ◽  
Delta Winglet

Heat transfer rate, pressure loss and efficiency are considered as the most important parameters in designing compact heat exchangers. Despite different types of heat exchangers, fin-and-tube compact heat exchangers are still common device in different industries due to the diversity of usage and the low space installation need. The efficiency of the compact heat exchanger can be increased by introducing the fins and increasing the heat transfer rate between the surface and the surroundings. Numerous modifications can be applied to the fin surface to increase heat transfer. Delta-winglet vortex generators (VGs) are known to enhance the heat transfer between the energy carrying fluid and the heat transfer surfaces in plate-fin-and-tube banks, but they have drawbacks as well. They increase the pressure loss and this should be considered. In this paper, the thermal efficiency of compact heat exchanger with VGs is investigated in different variations. The angle of attack, the length and horizontal and vertical position of winglet are the main parameters to consider. Numerical analyses are carried out to examine finned tube heat exchanger with winglets at the fin surface in a relatively low Reynolds number flow for the inline tube arrangements. The results showed that the length of the winglet significantly affects the improvement of heat transfer performance of the fin-and-tube compact heat exchangers with a moderate pressure loss penalty. In addition, the results show that the optimization cannot be performed for one criterion only. More parameters should be considered at the same time to run the process properly and improve the heat exchanger efficiency.

scholarly journals Effect of Attack Angle of Concave and Convex Winglets Vortex Generators on Thermal-Hydraulic Performance of Fin and Tube Heat Exchangers with Field Synergy Principle

2021 ◽  
Vol 39 (3) ◽  
pp. 797-809
Author(s):  
Syaiful ◽  
Bambang Yunianto ◽  
Carisya Dara Salsabila ◽  
Berkah Fajar T.K. ◽  
Maria F. Soetanto
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Pressure Drop ◽  
Heat Transfer Rate ◽  
Heat Exchangers ◽  
Transfer Rate ◽  
Convective Heat Transfer Coefficient ◽  
Attack Angle ◽  
Vortex Generators ◽  
Longitudinal Vortex

In fin and tube heat exchangers, the gas passing through the fin has a lower thermal conductivity than the fluid passing through the tube. The low thermal conductivity brings a high thermal resistance, which suppresses the heat transfer rate. A common practice to enhance fin-side heat transfer is to generate longitudinal vortex by mounting vortex generators (VGs) on the fin. This paper aims to investigate how longitudinal vortex generator (LVG) improves heat transfer and pressure drop. Numerical simulations were carried out to analyze three types of VGs. The installation of VGs was varied with the attack angle changing from 10°, 15°, to 20° with a 1-3-4-7 VG arrangement on the tube. The flow velocity was expressed in Reynolds number (Re) between 364 and 689. The enhancement of heat transfer rate and improvement of pressure drop were analyzed between three types of VG, three different attack angles, and four types of winglet installation, compared to baseline. The simulation results show that the highest convective heat transfer coefficient (84.85%) was achieved by the VG composed of seven concave delta winglet pairs (CDWPs) at the attack angle of 20° and Re = 689; CDWP VG provides the highest heat transfer improvement among all cases.

scholarly journals PERFORMANCE ENHANCEMENT FOR ROTARY AIR PREHEATER OF A THERMAL POWER PLANT

2020 ◽  
Vol 24 (06) ◽  
pp. 57-67
Author(s):  
Sinan Mazin Hazim ◽  
◽  
Mohammed H. Alhamdo ◽  
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Power Plant ◽  
Pressure Drop ◽  
Heat Transfer Rate ◽  
Thermal Power Plant ◽  
Transfer Rate ◽  
Thermal Power ◽  
Pumping Power ◽  
Air Preheater

The corrosion phenomenon is considered the main problems for air preheater in thermal power plant. The boiler flue gas contamination leads to decrease the air preheater performance and increases the maintenance cost, which causes the degradation of the cold end heating elements and thus leads to decrease the heat recovery rate. In this study, an experimental investigation was done for the transient thermal behavior and the pressure drop of the standard regenerative air preheater (Pmatrix) model, evaluating the performance factor, then modifying the air preheater (P+CG) model by changing the plates at the cold end last basket to the coarse gravel media. Since the gravel media have low thermal conductivity and predicted to give a high pressure drop, a new technique was done for the modified air preheater to compensate the low heat transfer rates and reduce the pressure drop in the gravel media by inserting bypass tubes at ratios (i and s), Which, the (i) model represents the inner aperture of tubes for the hot baskets facing to the inner aperture of tubes for the cold basket. While (s) model the insertion the tubes of the hot baskets as a staggered distribution with the tubes for the cold basket. The experimental investigation was carried out for the Reynolds number based on the test duct hydraulic diameter at a range of 24500<Re < 98000 for each charge and discharge periods. The experimental results are presented in terms of the average heat transfer rate and the pumping power for matrix models. The experimental measured results corroborated that the bypass tubes have a significant impact on improving the heat transfer rate and the pressure drop reduction of the modified air preheater matrix. The results showed that the best performance factor was achieved in the air preheater (P+CG+Ts) model which found to be in the range of 0.7-0.31 at high and low Reynolds. However, this improvement increased the pumping power by 13% than the (Pmatrix) model.

Sign in / Sign up

Export Citation Format

Share Document