The heat transfer equations for fully developed flow under quasisteady state conditions have. The experimental results showed that the helically twisted tape gave lower heat transfer coef. It was demonstrated that the squarecut twisted tape inserts can. Regarding reduced width twisted tape inserts, ayub and alfahed 11 reported an experimental investigation on fluid. This paper performs a simulation study of the heat transfer phenomena in a tubular uloop pipe.
A plain tube is tested and compared with the empirical correlations and are found to be in good agreement with the experimental data. An investigation of highly turbulent flow heat transfer enhancement through modified twisted tape inserts and nanofluids yousef vazifeshenas 1, reza yousefi gelourd 2, seyyed esmaeil rahimi 1 department of mechanical engineering, babol university of technology, babol, iran. In deep laminar flow, the most suitable device is the twisted tape. Experiments were carried out on different twisted tape inserts in a turbulent flow regime by choosing suitable reynolds number between 3100 and 39 000. A squarecut twisted tape insert in the heat exchanger has been adopted in 27. Heat transfer technique with twisted tape inserts are broadly used in several industries for their cost savings, lower maintenance requires and the fact is that they can be easily setup. The helically twisted tape was subjected to a comparative test with a typical helical tape. Pdf experimental study of the effect of twistedtape inserts on. Heat transfer enhancement by tapered twisted tape inserts. The geometrical configuration of vcut twisted tape vct inserts with a thickness 0. Pdf performance analysis of copper twisted tape inserts.
An investigation of highly turbulent flow heat transfer. Heat transfer augmentation using twisted tape inserts. It is found experimentally the heat transfer coefficient and nusselt number in a heat exchanger with copper twisted tape is higher by 9% and 9. Heat transfer coefficients for laminar flow of water and ethylene glycol in an electrically heated metal tube with two twistedtape inserts were determined experimentally. Promotion of heat transfer using twisted tape with v cuts to generate additional turbulent and to improve the heat transfer.
At any time that twisted tape tt inserts are used, in conjunction with the augmentation in the heat transfer rate, the pressure drop increases. Twisted tapes are static mixers produced from a length of metal tape that is twisted to obtain a regular helical profile using a suitable machine tool. Enhancement of heat transfer using fe3o4 water nanofluid. Augmentation of laminar flow heat transfer in tubes by means. Thermal performance of heat transfer devices can be improved by heat transfer enhancement techniques.
Mon6x 48 numerical analysis of heat transfer in a pipe using twisted tape inserts r. Enhancement of heat transfer using varying width twisted tape inserts. These techniques are used in heat exchangers which are used in process industries, airconditioning equipments, refrigerators thermal power plants, radiators for space vehicles and automobiles etc. Comparative study on performance of different twisted tape inserts in the absorber tube of parabolic trough collector ptc are presented in this paper. The heat transfer augmentation of plain twisted tape inserts for different twist ratios has been studied in this study. Augmentation of laminar flow heat transfer in tubes by. Results of these simulations are discussed in the paper. Pdf performance analysis of copper twisted tape inserts for. Effect of twisted tape inserts on heat transfer in a. The rate of thermal energy transfer in shell and tube heat exchangers or chiller condenser tubes makes them one of the most critical components, if not the heart, of the system. International communications in heat and mass transfer.
A heat exchanger is a device that transfers unneeded heat from one region to another, and transferred heat may be fully reused, thus improving energy efficiency. Augmentation of laminar flow heat transfer in tubes by means of. Cold and hot water were used as working fluids in inner and outer side of heat exchanger. Heat transfer enhancement by using twisted tape insert. Experimental analysis of augmentation in heat transfer. Effect of twisted tape insert on heat transfer during flow. Heat transfer enhancement in a tube with twisted tape. Heat transfer enhancement in a tube using ellipticalcut twisted tape inserts pratik p.
Swapnil 15 experimentally investigated the influences of twisted tapes and wire coil on pressure drop, friction factor f, heat transfer and thermal enhancement index. Numerical analysis of heat transfer in a pipe using. Experimental investigation on heat transfer and pressure. A passive method inserts refer to the additional arrangements made as an obstacle to fluid flow so as to augment heat transfer. The data obtained from plain tube were verified with the literature correlation to ensure the validation of simulation results. Present paper argues the underlying physical phenomenon of heat transfer and fluid flow through a pipe with twisted tape inserts. Heat transfer and pressure drop correlations for twistedtape. Numerical study on enhanced heat transfer by twisted tape. Turbulent flow can be created by introducing twisted tape inserts inside the inner cylinder of heat exchanger. The types of twisted tapes and their impact on heat transfer enhancement for laminar, transition and turbulent flow regimes have been presented in detail.
The nusselt number for fully developed flow was found to be a function of tape twist ratio, reynolds number, and prandtl number. Request pdf heat transfer augmentation using twisted tape inserts. Aug 25, 2018 cfd analysis of twisted tape inserts on heat transfer in a tube 3. In comparison with plain tube all twisted tape inserts would significantly enhance the heat transfer rate. Pdf effect of twisted tape insert on heat transfer during flow. The tube applied here has 17 mm of inner diameter and 1mm thickness. Augmentation of heat transfer in pipe flow using plain. At the beginning of the tape a hole is drilled, which is used to block the insert to the turbulator, in order to prevent it from being dragged away from the tube by the fluid. Heat exchanger, twisted tape inserts, nanofluids, concentric tube, heat transfer. Pdf an experimental investigation has been conducted to evaluate the effect of twisted tape inserts on augmentation of the heat transfer coefficient. The data are conducted using the plain twisted tape insert with five different twist ratios respectively.
Twisted tape design and analysis of heat exchanger with. Twisted tape turbulators are an economical means of enhancing heat transfer in new and existing equipment. Abstract twisted tape is widely used heat transfer enhancement technique. Internal flow in an enhanced tube having squarecut twisted tape. Also twisted tape tt is one of the main inserts which can improve heat transfer rate and it is studied completely through the current paper. Experimental investigation of heat transfer and friction factor characteristics in a double pipe heat exchanger fitted with typical twisted tape elements, were studied. Heat transfer efficiency can be increased by increasing the thermal conductivity of the working fluid. Heat transfer coefficients for laminar flow of water and ethylene glycol in an electrically heated metal tube with two twisted tape inserts were determined experimentally. Modification is proposed to van driest eddy diffusivity expression to the case of swirl flow generated by twisted tape inserts. For the experimental set up by reducing width of the helical twisted tape inserts with id of inside tube wdi0. They also presented the empirical correlations based on the experimental results of their study.
Numerical analysis of heat transfer in a pipe using twisted tape inserts r. Heat exchanger, twisted tape inserts, twisted tape inserts with different twisted ratio. The variously modified twisted tape inserts are widely researched and used to enhance heat transfer efficiency for heat exchangers. Inserts are widely used in pipe flow for heat transfer enhancement, since they can break the boundary layer and promote. Numerical analysis of heat transfer in a pipe using twisted. The classic twisted tape inserts have 15mm width and 1mm thickness with four twist ratios as 1. We have investigated the enhancement of heat transfer with mass flow in a pipe without insert, with full length and short length twisted tape inserts. In laminar flow, fluid particles travel in a longitudinal direction, and the only mode of heat transfer is conduction. The aluminium and stainlesssteel variable pitch twisted tape inserts showed an enhancement of overall heat transfer coefficient of 23. The results of varying twisted tape inserts with different twisted ratio have been compared with the values for the smooth tube. Heat transfer enhancement in circular tube using twisted.
It is common knowledge that enhancement is achieved by inducing a swirling and mixing action of tubeside fluid causing higher near wall velocities which eliminates thermal boundary layer and the corresponding insulating effect. Increase in nusselt number in plain twisted tape inserts with the twist ratio of 5. The current situation of the study on twisted tape inserts. The current situation of the study on twisted tape inserts in. The reynolds numbers were varied in the range 019000 with heat flux variation 14 to 22 kwm2 of smooth tube and 23 to 40 kwm2 for tube with inserts. Simulation of heat transfer in a tubular pipe using different. Analysis of heat transfer in pipe with twisted tape inserts. Its role in terms of heat transfer is known 2023 but it is not clear whether by using twisted tape and crude oil as a process fluid, fouling increases. Heat transfer enhancement in a tube with twisted tape inserts. Sewatkar college of engineering pune shivajinagar, pune, maharashtra, india 411005 cms. Prediction of the heat transfer in an air cooler equipped. Regarding reduced width twisted tape inserts, ayub and alfahed 11 reported an experimental investigation on fluid friction twisted tape inserts placed separately from the wall. By utilizing the twisted tape inserts, the flow becomes occlude and subsequently produce eddying due to increasing recirculation area between the closest wall surface and the twisted tape insert.
Analysis of heat transfer in pipe with twisted tape inserts avinash savekar, dhiraj jangid, madhura gurjar, vikrant patil, c. Overall an attempt is made to study the increase in efficiency of heat exchanger with help of nano fluids and twisted tape inserts. May 29, 2018 twisted tape enhances heat transfer in heat exchanger tubes by modifying the flow channel of the cooling fluid. In the same year, they also suggested that delta winglet twisted dwt tape inserts is more effective than the other typical twisted tape insert and dwt reduces the size of the heat exchange15. It was demonstrated that the squarecut twisted tape inserts can provide higher performance than the plain twisted tape inserts. The inner and outer diameters of the inner tube are 19. We observed that the transfer of heat is enhanced significantly with the increase of the length of inserts inside the computational domain. Evaluation of crude oil fouling formation in a heat. Icmiee18164 study of heat transfer enhancement in tubular. But these studies were not comprehensive enough to enrich students and designers to the subject of heat exchangers. Cfd analysis of twistedtape inserts on heat transfer in a tube 3. Twistedtape inserts as a strategy to improve heat transfer rates. Twisted tapes are the metallic strips twisted with some suitable techniques with desired shape and dimension, inserted in the flow.
Figure 1b shows the bent tube, fan and tube inserts used in the experiment. In some studies, researchers focused the thermal effects of twisted tape inserts in modified tube instead of smooth tube, for example. Numerical investigation of the heat transfer and friction factor characteristics of a circular fitted with vcut twisted tape vct insert with twist ratio and different cut depths, 1, and 1. Experimental investigation of heat transfer enhancement in. Energies free fulltext internal flow analysis of a heat. Heat transfer enhancement in concentric tube heat exchanger. Enhancement heat transfer in a tube fitted with passive. Eiamsaard thianpong 3 experimented on heat transfer enhancement in a tube using deltawinglet twisted tape inserts.
Gawandare et al 2014 reynolds number varied from 5000 to 16000. Experiments were carried out for plain tube withwithout twisted tape insert at constant wall heat flux and different mass flow rates. Heat transfer augmentation in tube using various twisted tape. Analysis of heat transfer in pipe with twisted tape inserts avestia. Numerical study of an exhaust heat recovery system using. From this experimental study the results can be concluded as follows.
It showed that the highest heat transfer rate was achieved for the twisted tape with twist ratio 3. Evaluation of crude oil fouling formation in a heat exchanger. In the present study, heat transfer from hot air to cold water by double pipe heat exchanger for plain tube and plain tube with twisted inserts is. We also found that, full length twisted tape inserts are more effective than comparing with the short length inserts and without insert. The more twist increased the heat transfer and decreased the friction factor. So heat transfer in a tube can be increased by fluid mixing with the help of using inserts 3. This work mainly focuses on the twisted tape inserts with different pitch. Heat transfer and pressure drop correlations for twistedtape inserts in isothermal tubes. To augment this positive process, many studies and investigations on automation technologies have been performed. Augmentation of convective heat transfer in the internal flows with tape inserts in tubes is a wellknown technique employed in industrial practice.
Heat transfer enhancement in a tube using ellipticalcut. Myroslaw marko, loose tightloose twist, twistedtape insert solar central receiver. Heat transfer enhancement in circular tube using twisted tape. Heat transfer augmentation in tube using various twisted.
In this work, a double pipe heat exchanger system is considered for studying the variation of effectiveness of the heat exchanger by inserting twisted tape. The twisted tapes were made of aluminum strip with. Augmentation of laminar flow heat transfer in tubes by means of twistedtape inserts. The range of reynolds number is considered under a uniform heat flux condition. Simulation of heat transfer in a tubular pipe using. Heat transfer behavior with conical ring and twisted tape inserts was investigated experimentally by promvonge and eiamsaard 9, and they report a 367% enhancement in heat transfer. Performance evaluation of heat transfer and friction. Energies free fulltext internal flow analysis of a.
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