scholarly journals Assessment of economic, thermal and hydraulic performances a corrugated helical heat exchanger filled with non-Newtonian nanofluid

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Muhammad Ibrahim ◽  
Ebrahem A. Algehyne ◽  
Tareq Saeed ◽  
Abdallah S. Berrouk ◽  
Yu-Ming Chu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Performance Evaluation ◽  
Heat Exchanger ◽  
Economic Analysis ◽  
Evaluation Criteria ◽  
Methyl Cellulose ◽  
Hydraulic Performance ◽  
Two Phase ◽  
Heat Transfer Efficiency ◽  
Helical Heat Exchanger

AbstractImproved heat transfer efficiency with considering economic analysis in heating systems is an interesting topic for researchers and scientists in recent years. This research investigates the heat transfer rate (HTR) and flow of non-Newtonian water-Carboxyl methyl cellulose (CMC) based Al2O3 nanofluid in a helical heat exchanger equipped with common and novel turbulators using two-phase model. The requirements for dimensions and cost reduction and also energy saving in thermal systems are the main goal of this study. According to gained results usage of corrugated channel in helical heat exchanger has a considerable influence on thermal and hydraulic performance evaluation criteria (THPEC) index of helical heat exchanger and can improve the THPEC index. Thus, Re = 5000 is obtained as an optimum value, in which the maximum THPEC value is achieved. As it is found in this paper, in case of using novel heat exchanger instead of the basic smooth system, the thermal properties (by considering Nusselt number) increases about 210%, the hydraulic performance (friction factor) reduces about 28%, performance evaluation criteria index increases about 57% and the material consumption (in case of similar THPEC) decreases about 31%. In another word, with considering economic analysis for the basic and novel system which has same efficiencies, the novel one has lower length and consequently 31% lower material.

scholarly journals On the Heat Transfer Enhancement of Plate Fin Heat Exchanger

2018 ◽  
Author(s):  
Yuan Xue ◽  
Zhihua Ge ◽  
Xiaoze Du ◽  
Lijun Yang
Keyword(s):  
Heat Transfer ◽  
Performance Evaluation ◽  
Heat Exchanger ◽  
Aspect Ratio ◽  
Evaluation Criteria ◽  
Swirl Flow ◽  
Design Parameters ◽  
Cfd Simulations ◽  
Enhancement Of Heat Transfer ◽  
Aspect Ratios

The plate fin heat exchanger is the compact heat exchanger applied in many industries because of its high thermal performance. To enhance the heat transfer of plate fin heat exchanger in further, three new kinds of wavy plate fins, namely perforated wavy fin, staggered wavy fin and discontinuous wavy fin are proposed and investigated by CFD simulations. The effects of key design parameters, including that of waviness aspect ratios, perforation diameters, stagger ratios and breaking distance are investigated, respectively, with the Reynolds number changes from 500 to 4500. It is found that due to the swirl flow and efficient mixing of fluid, the perforation, serration and breaking techniques are beneficial for the enhancement of heat transfer compared to the traditional wavy fin. At the same time, serration is beneficial to reduce the friction factor, and the breaking technique can reduce heat transfer area as well as enhance heat transfer performance. Through the performance evaluation criteria, the staggered wavy fin has an advantage over the small waviness aspect ratio compared to the perforated wavy fin. The maximum performance evaluation criteria (PEC), as high as 1.24, can be obtained for the perforated wavy fin at the largest waviness aspect ratio.

Thermal-Hydraulic Performance Analysis by Means of Rectangular Winglet Vortex Generators in a Channel: An Experimental Study

2021 ◽  
Vol 6 (3) ◽  
pp. 150-153
Author(s):  
Oktarina Heriyani ◽  
Mohamad Djaeni ◽  
. Syaiful
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Performance Evaluation ◽  
Heat Exchangers ◽  
Transfer Rate ◽  
Rectangular Channel ◽  
Evaluation Criteria ◽  
Hydraulic Performance ◽  
Vortex Generators ◽  
Fluid Flow Velocity

Vortex generators (VGs) are one of the effective passive models used to increase the heat transfer rate in heat exchangers. In this experiment, heat transfer from six cylinders heated to the airflow was improved by attaching rectangular winglet vortex generators (RWVGs) to a plate in a rectangular channel. The installation aimed to increase the value of the thermal-hydraulic performance evaluation criteria in the line. This experimental study was carried out by varying the fluid flow velocity from 0.4 m/s to 2 m/s with an interval of 0.2 m/s in the channel. Three pairs of VGs were arranged in both in-line and staggered configurations. The experimental results show that the thermal-hydraulic performance evaluation criteria for three pairs of vortex generators in the staggered configuration was 15.17% higher than the baseline, while the thermal-hydraulic performance of the in-line arrangement was 1.54% higher than the staggered one.

scholarly journals Effects of Fin Arrangements on Thermal Hydraulic Performance of Supercritical Nitrogen in Printed Circuit Heat Exchanger

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 861
Author(s):  
Shan Yang ◽  
Zhongchao Zhao ◽  
Yong Zhang ◽  
Zhengchao Chen ◽  
Min Yang
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Evaluation Criteria ◽  
Hydraulic Performance ◽  
Ansys Fluent ◽  
Printed Circuit ◽  
Flow And Heat Transfer ◽  
Transverse Distance ◽  
Fluent Simulation ◽  
Staggered Arrangement

The printed circuit heat exchanger (PCHE) with discontinuous fins is a novel type of compact and highly efficient plate heat exchanger, which has superior thermal hydraulic performance. The morphology and characteristics of the flow channel greatly affect the performance of the PCHE. The discontinuous airfoil fins are used in PCHE channel design because they can affect the flow and heat transfer by increasing the heat transfer area and the disturbance in the channel. In this paper, the effects of different staggered distance (Ls) and transverse distance (Lv) of airfoil fin arrangements on the heat transfer and flow of supercritical nitrogen in the PCHE are numerically simulated using ANSYS Fluent. Simulation results and subsequent analysis show that the appropriate decrease in Ls and reduction in Lv between the two rows of fins can improve the convective heat transfer of the PCHE. A fully staggered arrangement of fins (Ls = 1.2) and an appropriate increase in the Lv can mitigate pressure drop. The comprehensive performance of different channel geometries is compared by the performance evaluation criteria (PEC) in this study. It is shown that considering flow resistance and heat transfer, the comprehensive heat transfer performance can be enhanced by properly increasing the staggered distance and the vertical distance between fins. When Ls = 1.2 mm and Lv = 1.25 mm, the PEC value of the staggered channel is the highest, which is 11.6% higher than that of the parallel channel on average.

CFD-based structure optimization of plate bundle in plate-fin heat exchanger considering flow and heat transfer performance

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Yao Li ◽  
Haiqing Si ◽  
Jingxuan Qiu ◽  
Yingying Shen ◽  
Peihong Zhang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Heat Exchanger ◽  
Heat And Mass Transfer ◽  
Field Performance ◽  
High Specific Surface Area ◽  
Calculation Model ◽  
Air Separation ◽  
Transfer Efficiency ◽  
Heat Transfer Efficiency

Abstract The plate-fin heat exchanger has been widely applied in the field of air separation and aerospace due to its high specific surface area of heat transfer. However, the low heat transfer efficiency of its plate bundles has also attracted more attention. It is of great significance to optimize the structure of plate-fin heat exchanger to improve its heat transfer efficiency. The plate bundle was studied by combining numerical simulation with experiment. Firstly, according to the heat and mass transfer theory, the plate bundle calculation model of plate-fin heat exchanger was established, and the accuracy of the UDF (User-Defined Functions) for describing the mass and heat transfer was verified. Then, the influences of fin structure parameters on the heat and mass transfer characteristics of channel were discussed, including the height, spacing, thickness and length of fins. Finally the influence of various factors on the flow field performance under different flow states was integrated to complete the optimal design of the plate bundle.

scholarly journals Investigation of Overlapped Twisted Tapes Inserted in a Double-Pipe Heat Exchanger Using Two-Phase Nanofluid

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1656 ◽  
Author(s):  
Mehdi Ghalambaz ◽  
Hossein Arasteh ◽  
Ramin Mashayekhi ◽  
Amir Keshmiri ◽  
Pouyan Talebizadehsardari ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Performance Evaluation ◽  
Heat Exchanger ◽  
Evaluation Criterion ◽  
Twisted Tape ◽  
Performance Evaluation Criterion ◽  
Twisted Tapes ◽  
Double Pipe ◽  
Pipe Heat

This study investigated the laminar convective heat transfer and fluid flow of Al2O3 nanofluid in a counter flow double-pipe heat exchanger equipped with overlapped twisted tape inserts in both inner and outer tubes. Two models of the same (co-swirling twisted tapes) and opposite (counter-swirling twisted tapes) angular directions for the stationary twisted tapes were considered. The computational fluid dynamic simulations were conducted through varying the design parameters, including the angular direction of twisted tape inserts, nanofluid volume concentration, and Reynolds number. It was found that inserting the overlapped twisted tapes in the heat exchanger significantly increases the thermal performance as well as the friction factor compared with the plain heat exchanger. The results indicate that models of co-swirling twisted tapes and counter-swirling twisted tapes increase the average Nusselt number by almost 35.2–66.2% and 42.1–68.7% over the Reynolds number ranging 250–1000, respectively. To assess the interplay between heat transfer enhancement and pressure loss penalty, the dimensionless number of performance evaluation criterion was calculated for all the captured configurations. Ultimately, the highest value of performance evaluation criterion is equal to 1.40 and 1.26 at inner and outer tubes at the Reynolds number of 1000 and the volume fraction of 3% in the case of counter-swirling twisted tapes model.

EXERGOECONOMIC ANALYSIS ON ENHANCED HEAT TRANSFER SURFACES AT LOW TEMPERATURE

2007 ◽  
Vol 21 (18n19) ◽  
pp. 3500-3502
Author(s):  
DENG-FANG RUAN ◽  
YOU-RONG LI ◽  
SHUANG-YING WU ◽  
BO LAN
Keyword(s):  
Heat Transfer ◽  
Performance Evaluation ◽  
Low Temperature ◽  
Evaluation Criteria ◽  
Enhanced Heat Transfer ◽  
Second Law Analysis ◽  
Augmentation Techniques ◽  
Transfer Cost ◽  
Exergoeconomic Analysis ◽  
New Criterion

The exergoeconomic analysis is carried out on enhanced heat transfer surfaces at low temperature. A new criterion for evaluating the performance of enhanced heat transfer surfaces at low temperature is proposed. It can be applied to various augmentation techniques and generalizes the performance evaluation criteria obtained by means of the first and second law analysis. The validity of the new performance evaluation criterion is illustrated by the analysis of heat transfer characteristics at low temperature and assessment of the heat transfer cost of two types of enhanced heat transfer surfaces.

Development of Heat Exchanger Fouling Model and Preventive Maintenance Diagnostic Tool

2007 ◽  
Vol 2 (2) ◽  
Author(s):  
H. Zabiri ◽  
V. R. Radhakrishnan ◽  
M. Ramasamy ◽  
N. M. Ramli ◽  
V. Do Thanh ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Predictive Model ◽  
Diagnostic Tool ◽  
Preventive Maintenance ◽  
Heat Exchangers ◽  
Waste Heat ◽  
A Priori ◽  
Transfer Efficiency ◽  
Heat Transfer Efficiency

The Crude Preheat Train (CPT) is a set of large heat exchangers which recover the waste heat from product streams back to preheat the crude oil. The overall heat transfer coefficient in these heat exchangers may be significantly reduced due to fouling. One of the major impacts of fouling in CPT operation is the reduced heat transfer efficiency. The objective of this paper is to develop a predictive model using statistical methods which can a priori predict the rate of the fouling and the decrease in heat transfer efficiency in a heat exchanger in a crude preheat train. This predictive model will then be integrated into a preventive maintenance diagnostic tool to plan the cleaning of the heat exchanger to remove the fouling and bring back the heat exchanger efficiency to their peak values. The fouling model was developed using historical plant operating data and is based on Neural Network. Results show that the predictive model is able to predict the shell and tube outlet temperatures with excellent accuracy, where the Root Mean Square Error (RMSE) obtained is less than 1%, correlation coefficient R2 of approximately 0.98 and Correct Directional Change (CDC) values of more than 90%. A preliminary case study shows promising indication that the predictive model may be integrated into a preventive maintenance scheduling for the heat exchanger cleaning.

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