scholarly journals RESEARCH OF THE FUNCTIONING AND OPTIMIZATION PROCESS OF THE STRUCTURAL-TECHNOLOGICAL PARAMETERS

2020 ◽  
pp. 142-150
Author(s):  
Vitaliy Yaropud
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Flow Rate ◽  
Thermal Power ◽  
Design Parameters ◽  
Theoretical Studies ◽  
Technological Parameters ◽  
Air Flows ◽  
Counter Current ◽  
Pipe Heat

Domestic and foreign scientists in recent years have performed a considerable amount of scientific research on the biological justification of optimal combinations of microclimate parameters required for the normal development of animals. However, the results of the studies do not allow one to specify the optimal parameters for different species of animals, taking into account their age, sex, weight and level of feeding. While it is possible to specify rather wide limits of change of temperature and relative humidity of air at which productivity is maximum, and technical and economic efficiency is approximately the same. Providing microclimate regulations in livestock premises is associated with significant costs of electricity and heat, which is about 17% of the producers' costs. To create a microclimate in livestock premises based on the above technological parameters and the analysis of the design features of the recuperators, two design and technological schemes of the three-pipe recuperator, which differ in the directions of movement of air flows, are proposed. The purpose of the research is to increase the efficiency of the technological process of functioning of the three-pipe recuperator for livestock premises by substantiating its structural and mode parameters. The results of theoretical studies of pneumatic losses in the three-pipe recuperator determined the dependence of pressure and power losses on the length of the air duct of the three-pipe recuperator, the radius of the external duct and the volume flow rate of air. As a result of theoretical studies, a mathematical model of the heat transfer process in a three-pipe heat exchanger was developed, with condensation in it, which allows to determine the temperature distribution of air flows by its length and its thermal capacity. The results of theoretical studies of the process of heat transfer in the design and technological schemes of a three-pipe recirculator with counter-current and direct-current showed that the counter-current variant is more effective. Optimization of the results of theoretical studies allowed us to determine the dependence of the design parameters of the three-pipe heat exchanger on the volumetric flow rate of air, subject to the highest useful thermal power.

Optimizing Effectiveness of Double Pipe Heat Exchanger Using Nanofluid and Different Porous Fins Arrangement

2021 ◽  
Author(s):  
Avinash Kumar ◽  
Vinay Arya ◽  
Chirodeep Bakli
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Design Parameters ◽  
Heat Transfer Characteristics ◽  
Pressure Losses ◽  
Porous Fin ◽  
Transfer Characteristics ◽  
Porous Fins ◽  
Double Pipe ◽  
Pipe Heat

Abstract A numerical study is carried out to investigate the effect of porous fins in counter-flow Double Pipe Heat Exchanger (DPHE). Four DPHE with different porous fin arrangements is simulated for varying Darcy number, fin height, and the number of fins and compared with the conventional DPHE with no porous fins. The Darcy-Brinkman-Forchheimer equation is employed to model the flow in the porous fins considering fixed Re = 100. Al2O3-H2O nanofluid and water are used as hot and cold fluids respectively. Stainless steel is used as porous material with a porosity of 0.65. Results are evaluated in terms of effectiveness and Performance Evaluation Criterion (PEC). The effectiveness of the heat exchanger is used to analyze the heat transfer characteristics whereas the PEC is used to analyze the heat transfer characteristics considering pressure losses also. We evaluated maximum enhancement in thermal performance using effectiveness analysis and through PEC study we evaluated optimal effectiveness and corresponding design parameters. It is shown that utilizing porous fins in DPHE enhances the heat transfer by 134.3%. However, along with enhancement in heat transfer, the pressure losses also enhance which makes the application of porous fin non-viable. Therefore, using the PEC study we obtained optimal design parameters (Da = 10−3, hf = 4 cm, and n = 30) which adapts porous fin viable with enhancement in heat transfer by 66.38%.

scholarly journals Effect of Twisted-Tape Turbulators and Nanofluid on Heat Transfer in a Double Pipe Heat Exchanger

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Heydar Maddah ◽  
Reza Aghayari ◽  
Morshed Farokhi ◽  
Shabnam Jahanizadeh ◽  
Khatere Ashtary
Keyword(s):  
Heat Transfer ◽  
Titanium Dioxide ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Friction Factor ◽  
Flow Rate ◽  
Twisted Tape ◽  
Double Pipe ◽  
Pipe Heat

Heat transfer and overall heat transfer in a double pipe heat exchanger fitted with twisted-tape elements and titanium dioxide nanofluid were studied experimentally. The inner and outer diameters of the inner tube were 8 and 16 mm, respectively, and cold and hot water were used as working fluids in shell side and tube side. The twisted tapes were made from aluminum sheet with tape thickness (d) of 1 mm, width (W) of 5 mm, and length of 120 cm. Titanium dioxide nanoparticles with a diameter of 30 nm and a volume concentration of 0.01% (v/v) were prepared. The effects of temperature, mass flow rate, and concentration of nanoparticles on the overall heat transfer coefficient, heat transfer changes in the turbulent flow regimeRe≥2300, and counter current flow were investigated. When using twisted tape and nanofluid, heat transfer coefficient was about 10 to 25 percent higher than when they were not used. It was also observed that the heat transfer coefficient increases with operating temperature and mass flow rate. The experimental results also showed that 0.01% TiO2/water nanofluid with twisted tape has slightly higher friction factor and pressure drop when compared to 0.01% TiO2/water nanofluid without twisted tape. The empirical correlations proposed for friction factor are in good agreement with the experimental data.

scholarly journals Thermodynamic performance evaluation of an air-air heat pipe heat exchanger

2014 ◽  
Vol 18 (4) ◽  
pp. 1343-1353 ◽  
Author(s):  
Mohan Kumar ◽  
S.C. Kaushik ◽  
S.N. Garg
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Pipe ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Heat Pipes ◽  
Heat Transfer Analysis ◽  
Thermodynamic Performance ◽  
Pipe Heat

In this paper, heat transfer analysis for an air-air heat exchanger was experimentally carried out to find its thermal performance and effectiveness. Air-air heat exchanger equipped with finned heat pipes was considered for the experimentation. Mass flow rate of air was considered in between 0.24 to 0.53 [kg/sec]. The temperature at the condenser side of the heat pipe heat exchanger was kept constant at around 23 [?C] and at the evaporator part it was varied from 88 to 147 [?C]. The performance of heat pipe heat exchanger was evaluated at different mass flow rate of air, in terms of effectiveness and compared with its corresponding value found by theoretical analysis.

scholarly journals Thermal Analysis on Hydrothermal Performance of Double Pipe Heat Exchanger with Single and Double Helical Tape

2019 ◽  
Vol 9 (2) ◽  
pp. 1965-1972
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Industrial Process ◽  
Design Parameters ◽  
Cfd Simulations ◽  
Economic Point ◽  
Double Pipe ◽  
Pipe Heat

Double pipe heat exchanger has wide applications in industrial process. Thermo-hydro performance plays an important role from the economic point of view. Different enhancement techniques are available for the improvement of heat transfer. In this study the hydrothermal performance of double pipe heat exchanger with single and double HTI on inner pipe of double pipe heat exchanger were experimentally examined. Two types of inner tubes with single and double helical tape was fabricated. Experiments were performed by different mass flow rate of annulus side in the range of 0.072- 0.21 kg/s varied. In order to validate the result three dimensional CFD simulations are performed, using Fluent software. CFD simulations analysis was done under turbulent flow conditions. Key design parameters such as heat transfer coefficient and Nusselt number are evaluated in order to predict the performance of DPHE. Findings from this study shows that hydrothermal performance of double pipe heat exchanger with double helical tape is better than single HTI. Moreover both the results of CFD simulation & experimental one are in good agreement. Therefore, the present study will help the manufacturers in providing the better thermal performance of DPHE.

scholarly journals Implementation of GRNN for Evaluating the Pressure Drop and Heat Transfer in a Heat Exchanger by Utilizing Triple Elliptical Leaf Angle Strips with Same Orientation and Opposite Direction

2019 ◽  
Vol 8 (6) ◽  
pp. 4333-4340
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Opposite Direction ◽  
Heat Exchangers ◽  
Industrial Applications ◽  
Design Parameters ◽  
Leaf Angle ◽  
Statistical Tool ◽  
Experimental Values ◽  
Pipe Heat

Heat exchangers are the basic devices which are used in many areas wherever applications of heat flow occurs. Its usage varies from common domestic devices to mighty industrial applications. The performance of the heat exchanger shows a very important role for its utilization in many aspects. This performance is not dependent on the design parameters in a particular relationship hence experimental values for thermal performance are taken by utilizing three elliptical leaf strips in a tube and pipe heat exchanger. The three elliptical leaves used in experiment has major to minor axes ratios as 2:1 and distance of 50 mm between two leaves are arranged at different angular orientations from 00 to 1800 with 100 intervals. The leaves are placed in the tube side with same orientation and opposite direction of flow and experimentation is conducted to obtain the values. Based on these datasets available a statistical tool is utilized known as GRNN for the comparison between these obtained experimental values & GRNN values. From this comparison the percentage of error between the values is identified as result.

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.

Upgrade and Shakedown Test of a High Temperature Fluoride Salt Test Loop

2018 ◽  
Author(s):  
Xiangbo Kong ◽  
Yuan Fu ◽  
Jianyu Zhang ◽  
Huiju Lu ◽  
Naxiu Wang
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Heat Exchanger ◽  
Flow Rate ◽  
Storage Tank ◽  
Base Alloy ◽  
High Vacuum ◽  
Electric Heater ◽  
Batch Mode ◽  
Test Loop

A FLiNaK high temperature test loop, which was designed to support the Thorium Molten Salt Reactor (TMSR) program, was constructed in 2012 and is the largest engineering-scale fluoride loop in the world. The loop is built of Hastelloy C276 and is capable of operating at the flow rate up to 25m3/h and at the temperature up to 650°C. It consists of an overhung impeller sump-type centrifugal pump, an electric heater, a heat exchanger, a freeze valve and a mechanical one, a storage tank, etc. Salt purification was conducted in batch mode before it was transferred to and then stored in the storage tank. The facility was upgraded in three ways last year, with aims of testing a 30kW electric heater and supporting the heat transfer experiment in heat exchanger. Firstly, an original 100kW electric heater was replaced with a 335kW one to compensate the overlarge heat loss in the radiator. A pressure transmitter was subsequently installed in the inlet pipe of this updated heater. Finally, a new 30kW electric heater was installed between the pump and radiator, the purpose of which was to verify the core’s convective heat transfer behavior of a simulator design of TMSR. Immediately after these above works, shakedown test of the loop was carried out step by step. At first the storage tank was gradually preheated to 500°C so as to melt the frozen salt. Afterwards, in order to make the operation of transferring salt from storage tank to loop achievable, the loop system was also preheated to a relatively higher temperature 530°C. Since the nickel-base alloy can be severely corroded by the FLiNaK salt once the moisture and oxygen concentration is high, vacuum pumping and argon purging of the entire system were alternatively performed throughout the preheating process, with the effect of controlling them to be lower than 100ppm. Once the salt was transferred into the loop, the pump was immediately put into service. At the very beginning of operation process, it was found that flow rate in the main piping could not be precisely measured by the ultrasonic flow meter. Ten days later, the pump’s dry running gas seal was out of order. As a result, the loop had to be closed down to resolve these issues.

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