Helical Coil Heat Exchanger Research Articles

Comparative experimental study on the thermal and hydraulic performances of capillary box heat exchanger and helical coil heat exchanger for surface water-source heat pump

The thermal and hydraulic performances of front-end heat exchangers significantly influence the energy efficiency of surface water-source heat pumps. To evaluate the performance of a capillary box heat exchanger (CBHE), a comparative study between the CBHE and a conventional helical coil heat exchanger (HCHE) was conducted under different tube velocities, heat transfer media, and temperatures. The comparison considered not only traditional metrics, such as the heat transfer coefficient, heat transfer efficiency, and pressure drop, but also the volume heat transfer coefficient and two thermal-hydraulic comprehensive performance parameters: the modified Colburn–Fanning factor ratio (JFK) with larger-the-better characteristics and the electricity consumption to extracted or rejected heat quantity ratio (EHR) with smaller-the-better characteristics. The results indicated that the heat transfer coefficient, heat transfer efficiency, and volume heat transfer coefficient of the CBHE were 10.1 W/(m2.°C)–25.58 W/(m2.°C), 34 %–45 %, and 1140 W/(m3.°C)–1416 W/(m3.°C) larger than those of the HCHE, whereas its total pressure drop was only 15 %–21 % of that of the HCHE. Additionally, the JFK and EHR of the CBHE were approximately three times and 11 %–16 %, respectively, those of the HCHE. This study serves as a reference for selecting and designing front-end heat exchangers.

Second law of thermodynamics, heat transfer, and pumping power analyses of water and ionic liquid mixture based MXene nanofluids in a shell and helical coil heat exchanger

Heat exchangers are extensively employed across diverse sectors for efficient thermal (heat)transfer between two fluids, specifically from a hot fluid to a cold fluid. Nanofluids are promising heat transfer fluids that exhibit exceptional thermal performance in heat exchangers. The present study examines the thermodynamic second law efficiency analysis of a shell and helical coil heat exchanger utilizing MXene/80:20% water+[MMIM][DMP] (mass percentage) based ionanofluids. An analytical investigation was conducted on the heat transfer coefficient, entropy generation rate, and exergy efficiency of a shell and helical coil heat exchanger, considering particle weight loadings from 0.2% to 1.0%, Reynolds numbers from 500 to 4300, and flow rates from 0.5 to 3.5 L/min. In the base fluid, at 1.0 wt.% and at a Reynolds number of 3598, the increase in heat transfer, Nusselt number, friction factor, pressure drop, effectiveness, and frictional entropy generation are 45.59%, 28.27%, 15.19%, 12.56%, 17.20%, and 16.21%, respectively. Concurrently, thermal entropy generation, and total exergy destruction were reduced by 46.23% and 20.08%, respectively. The second law (exergy) efficiency and thermal performance factor are improved by 34.04% and 1.384-times, respectively, at 1.0 wt.% and at a Reynolds number of 3598, compared to the base fluid. The data from the current study is corroborated by existing literature. New correlations were developed from the computed data points to estimate the Nusselt number and friction factor.

Effect of air bubble injection on the thermal performance of a vertical helical coiled tube heat exchanger: an experimental study

This study investigates the effect of air bubble injection on the thermal performance of a vertical counter-current coiled tube heat exchanger. A cylindrical PVC shell (height: 500 mm, diameter: 152.4 mm) was constructed to carry a copper coil with 11 regular turns and covered approximately 76% and 75% of the total shell height and diameter, respectively. The key operational parameters involving the shell side flow rate (2–10 L/min), the coil side flow rate (1–2 L/min), the air flow rate (0–10 L/min) and the temperature difference between the hot and cold fluids ((20 °C, 30 °C and 36 °C) were tested to determine the overall heat transfer coefficient (U). Air was injected into the shell side of the heat exchanger as bubbles with an average diameter of approximately 100 μm via a porous sparger. The results showed that air injection significantly enhanced U, with the highest improvement (158%) occurring at an air flow rate of 6 L/min, while the minimum improvement was 34%. Furthermore, the ratio of the overall heat transfer coefficient with air injection to that without air injection had its maximum value at a shell side flow rate of 6 L/min.

Evaluation of a helical coil heat exchanger in a forced convection environment

Evaluation of a helical coil heat exchanger in a forced convection environment

A Review of Thermochemical Energy Storage Systems for District Heating in the UK

Thermochemical energy storage (TCES) presents a promising method for energy storage due to its high storage density and capacity for long-term storage. A combination of TCES and district heating networks exhibits an appealing alternative to natural gas boilers, particularly through the utilisation of industrial waste heat to achieve the UK government’s target of Net Zero by 2050. The most pivotal aspects of TCES design are the selected materials, reactor configuration, and heat transfer efficiency. Among the array of potential reactors, the fluidised bed emerges as a novel solution due to its ability to bypass traditional design limitations; the fluidised nature of these reactors provides high heat transfer coefficients, improved mixing and uniformity, and greater fluid-particle contact. This research endeavours to assess the enhancement of thermochemical fluidised bed systems through material characterisation and development techniques, alongside the optimisation of heat transfer. The analysis underscores the appeal of calcium and magnesium hydroxides for TCES, particularly when providing a buffer between medium-grade waste heat supply and district heat demand. Enhancement techniques such as doping and nanomaterial/composite coating are also explored, which are found to improve agglomeration, flowability, and operating conditions of the hydroxide systems. Furthermore, the optimisation of heat transfer prompted an evaluation of heat exchanger configurations and heat transfer fluids. Helical coil heat exchangers are predominantly favoured over alternative configurations, while various heat transfer fluids are considered advantageous depending on TCES material selection. In particular, water and synthetic liquids are compared according to their thermal efficiencies and performances at elevated operating temperatures.

Numerical investigation of thermal-hydraulic performance enhancement in helical coil heat exchangers with twisted tube geometries

This numerical study examines the thermal-hydraulic performance of helical coil heat exchangers (HCHEs) using twisted tubes versus conventional circular tubes. The effects of Reynolds number (Re = 10,000 to 100,000), pitch length (11, 7.2, 5.5, 3.6 mm), and twisted tube orientation (co-current, counter-current) on heat transfer efficiency and pressure drop were investigated. The results show that higher Reynolds numbers can reduce the Resistance factor by approximately 25 % and improve heat transfer by approximately 35 %. An optimal pitch length of 5.5 mm was found to balance enhanced heat transfer and manageable pumping costs. Twisted tubes demonstrate significant performance advantages at lower Re, with 20–33 % higher Performance Evaluation Criterion (PEC) values compared to circular tubes. However, the benefit diminishes at higher Re, with less than 10 % PEC increase. Implementing counter-current twisted tube configurations leads to approximately 13 % higher Nusselt number and 11 % higher Resistance factor, resulting in a 10 % overall PEC improvement. These findings highlight the superior thermal-hydraulic performance of twisted tubes in HCHE applications, especially at lower Reynolds numbers. Future work could explore different fluids, advanced optimization, energy analysis, cost assessment, and additional geometric parameters to further enhance twisted tube heat exchanger design and performance.

Comparison of heat transfer characteristics of a heat exchanger with straight helical tube and a heat exchanger with coiled flow reverser

Vertical shell and coiled tube heat exchangers are an important aspect of numerous industrial processes and are renowned for their high heat transfer efficiency, versatility, compact design, easy manufacturability and maintenance. As a novel technique, a coiled flow reverser was used to enhance the thermal performance of shell and coiled tube heat exchangers. Therefore, the impact of employing a coiled flow reverser on the heat transfer characteristics and pressure drop in a counter-current shell and tube heat exchanger is investigated using both numerical and experimental approaches. The results are compared to a straight helical coiled tube heat exchanger. The numerical simulations were carried out by employing computational fluid dynamics (CFD) techniques, and the SIMPLE scheme was implemented through the second-order upwind discretization method. The laboratory device used for experimentation features a shell with an inner diameter of 15 cm, and the coil pitch and coil diameter of both coiled tubes are set at 3 cm and 12.1 cm, respectively. Results reveal that the overall heat transfer coefficient of the heat exchanger with a coiled flow reverser is 39.5 % to 49.9 % higher than that of the heat exchanger with a straight helical tube. The effectiveness ratio of the heat exchanger with coiled flow reverser to the straight helical tube heat exchanger ranges from 1.254 to 1.379. Optimal results are observed at a cold flow rate of 6 LPM and a hot flow rate of 1 LPM for both heat exchangers. Additionally, the coiled flow reverser enhances heat transfer performance at the cost of increased pressure drop. Numerical results are in good agreement with experimental findings, establishing the reliability of the study.

An Investigation on Concurrent and Countercurrent Heat Transfer Performance in a Double Pipe Helical Coil Heat Exchanger Using CFD

An Investigation on Concurrent and Countercurrent Heat Transfer Performance in a Double Pipe Helical Coil Heat Exchanger Using CFD

Experimental investigation of shell and helical coiled heat exchanger with Al2O3 nano-fluid with wide range of particle concentration

The purpose of this study is to experimentally enhance the heat exchange rate of the shell and helical coil tube heat exchanger by mixing water with aluminum oxide (Al2O3) nanoparticles, as well as to explore the effect of inlet thermal parameters on the performance of the heat exchanger. A test rig was constructed to investigate the influence of particle concentration, and inlet temperatures on the performance of nano-fluid. Parameters such as Nusselt number, pressure drop, performance evaluation criteria (PEC) are considered to rate the performance of the nano-particle with the heat exchanger. In this study a wider range of particle concentration is considered, which varies from 0.0%–0.75%. Experiments with and without nanoparticles are carried out under identical working conditions. By analyzing the experimental data, it was found that nanoparticles significantly improve the coefficient of heat transfer inside the helically coiled tube. From sensitivity analysis, it is obseerved that there is a slight decrease in Nusselt number of the nano-fluid with increase in inlet temperatures of the nano-fluid and the cooling water. Furthermore, it is concluded that an 8.5% increase in PEC value is observed with increase in particle concentration from 0.15% to 0.75%.

Heat transfer analysis of subcooled flow boiling in copper foam helical coiled heat exchanger – A pore-scale numerical study

High performance thermal energy systems are crucial in fulfilling the growing demand of thermal energy. Consequently, numerous heat transfer enhancements have been proposed. Some of the promising methods are boiling flow heat transfer, helical coiled tube and metal foam insert. Although the performance of each strategy has been extensively studied, based on our literature review, the effectiveness of combining these strategies has not been investigated. This missing information may impede further development of efficient heat transfer systems. This study is therefore performed to investigate subcooled flow boiling heat transfer in helical tube with copper foam insert. A high-resolution three-dimensional pore scale model that considers the shape, porosity and pore density of the metal foam is developed and validated against the published experimental results. Using the model, the effect of inlet temperature, mass flux, wall heat flux, porosity, pore density and half-filled metal foam are studied. The results suggest that operating parameters have mild effects on the heat transfer performance. In contrast, porosity and pore density show significant influence in heat transfer coefficient and pressure drop. It has also been found that total heat transfer surface area and base area are better in characterizing heat transfer in pore-scale level than porosity and pore density at pore-scale level. Moreover, implementing metal foam at outer half of the tube is observed to offer slightly better heat transfer than implementing it at the inner side by around 4.8%. Overall, this study indicates that helical metal foam tubes offer the best performance at mass flux of 200 kg/m2∙s with performance index of 0.72, while straight tubes with 0.90 porosity has the highest performance index of 0.66. Empirical correlations to relate dimensionless parameters to the Nusselt number and friction factor is generated. Finally, the model developed in this study can serve to provide guidelines for the upcoming studies in boiling in metal foam structure and assist in designing metal foam heat exchangers.

Numerical investigation of coupled heat transfer and flow characteristics in helical coil heat exchanger for mine water waste heat recovery

To efficiently recover waste heat from mine water, this study numerically investigates the flow and heat transfer performance of a tube-shell coupled helical coil heat exchanger (HCHE), under high Reynolds number conditions. The effects of inlet water temperature, mass flow rate (m), tube diameter (d), and helix pitch (P) on the tube side, shell side, and overall performance are analyzed. Performance metrics include friction factor (f), Nusselt number (Nu), overall heat transfer coefficient (U), heat transfer rate, and the Performance Evaluation Criteria (PEC) number. Specifically, this study focuses on detailed observation and analysis of the shell-side flow and temperature fields. Findings reveal that enlarging d from 30 mm to 50 mm results in a 32.55% decrease in U, whereas increasing P from 50 mm to 200 mm boosts U by 8.02%. The highest PEC number of HCHE is 2.43, observed in conditions of P = 50 mm, d = 30 mm, and mc = 4 × 103 kg/h. Correlations for fc, Nuc, and Nush are proposed based on simulation results. This study provides a theoretical basis for the design and structural optimization of HCHE in the mine water waste heat recovery applications.

Numerical research of an internal and external-corrugated tube-in-tube helical coil heat exchanger

ABSTRACT To effectively enhance the heat transfer of a tube-in-tube helical coil heat exchanger, a novel internal and external-corrugated tube-in-tube helical coil was proposed by improving both the inner and outer tubes. The impact of the corrugation layout on the annular region’s heat transfer property was simulated. The effect of periodically distributed corrugations on flow patterns and the local Nusselt on the inner tube wall was explored. Furthermore, by comparing the fluid’s velocity and temperature field contour in traditional helical coil and novel helical coil, the enhanced heat transfer mechanism was discovered. Finally, the effects of Re, dimensionless depth H, and dimensionless pitch S of corrugations on the annular region’s heat transfer, flow resistance and entropy generation were analyzed. The results showed that annular region’s heat transfer could be improved due to the periodically distributed corrugations. The local Nu distribution on the corrugated inner tube wall was similar to that of ordinary inner tube, while changed periodically due to the continuous influence of corrugations. The number of Nu and f increased by 53% ~72% and 40% ~120% with the dimensionless corrugation depth and dimensionless pitch being 0.15 and 1.5, respectively. The comprehensive heat transfer performance PEC reached 1.2 ~ 1.6, and cross-arranged inner and outer tube corrugations were more favorable for heat transfer than the corresponding arrangement, when Re = 6000, H3 structure has the highest S t , S f and S gen , which are 0.934W/K, 0.379 W/K and 1.312W/K, respectively. Increasing H and decreasing S could enhance the Nu, f and entropy generation. The values of PEC decreased with increasing S, while with the increment of H, PEC increased and decreased, respectively when Re was in the range of (2000, 4000) and (4000, 6000). In the study range, changing H and S could increase Nu by 40.3%–97.3%, 31.7%–96.8%, and f by 11.7%–176.5%, 16.4%–180.9%, respectively. The final comprehensive heat transfer performance increased by 12.8%-65.9%. Finally, the prediction correlation formulas of Nu and f in NTTHC annular region with high correlation is proposed.

Mathematical Modelling and Design of Helical Coil Heat Exchanger for Production of Hot Air for Fluidized Bed Dryer

Mathematical Modelling and Design of Helical Coil Heat Exchanger for Production of Hot Air for Fluidized Bed Dryer

Numerical Study of Flow and Heat Transfer Characteristics for Al2O3 Nanofluid in a Double-Pipe Helical Coil Heat Exchanger.

To numerically investigate the flow and heat transfer characteristics of a water/Al2O3 nanofluid in a double-pipe helical coil heat exchanger, we simulated a two-phase Eulerian model to predict the heat transfer coefficient, Nusselt number, and pressure drop at various concentrations (i.e., volume fraction) and under diverse flow rates at the steady state. In this simulation, we used the k-epsilon turbulence model with an enhanced wall treatment method. The performance factor of the nanofluid was evaluated by accounting for the heat transfer and pressure drop characteristics. As a result, the heat transfer was enhanced by increasing the nanofluid concentration. The 1.0 vol.% nanofluid (i.e., the highest concentration) showed a heat transfer coefficient 1.43 times greater than water and a Nusselt number of 1.38 times greater than water. The pressure drop of nanofluids was greater than that of water due to the increased density and viscosity induced using nanoparticles. Based on the relationship between the Nusselt number and pressure drop, the 1.0 vol.% nanofluid was calculated to have a performance factor of 1.4 relative to water, indicating that the enhancement rate in heat transfer performance was greater than that in the pressure drop. In conclusion, the Al2O3 nanofluid shows potential as an enhanced working fluid in diverse heat transfer applications.

Effect of Water-Based Nanofluids on the Generation of Entropy in a Shell and Helical Coil Heat Exchanger

A forced convection finding proves that entropy was generated as a result of the heat transfer between the fluids on the coil and the fluids on the shell side. It was found that entropy generation was affected by nanofluid concentration, coil-side fluid flow rate, shell-side fluid temperature, and agitator speed (500 rpm, 1000 rpm, and 1500 rpm) in this paper. The nanoparticle (Al2O3, CuO, and TiO2) weight fractions ranged from 0.3 to 2%. This paper investigates the friction entropy generation rate, the entropy generation ratio, and the thermal entropy generation rate of various nanofluids in laminar and turbulent flow conditions, using existing correlations to guide the investigation. The results revealed that the generation of entropy increased as the Dean number, SS, and fluid temperature on the shell side of the reactor were increased in the laboratory. And, found that the maximum entropy generation rate of Al2O3/water, CuO/water, and TiO2/water nanofluids occurred at 56.4 percent by weight of the nanofluid, 62.1 percent by weight of the nanofluid, and 48.1 percent by weight of the nanofluid.

CFD simulation of helical coil heat exchanger with Different coil pitch to heating heavy fuel oil

CFD simulation of helical coil heat exchanger with Different coil pitch to heating heavy fuel oil

Heat transfer in helical coil heat exchanger: An experimental parametric study

Heat transfer in helical coil heat exchanger: An experimental parametric study

Enhancement of heat transfer in helical coil heat exchangers using nano-fluids

Enhancement of heat transfer in helical coil heat exchangers using nano-fluids

Radiation heat transfer of hybrid nanofluid stagnation point flow across a stretching porous cylinder

The current study provides a comprehensive analysis of MHD hybrid nanofluids and stagnation point flow toward a porous stretched cylinder in the presence of thermal radiation. Here, alumina and copper are considered the hybrid nanoparticles, while water is the base fluid. To begin, the required similarity transformations are applied to transform the nonlinear coupled PDEs into nonlinear coupled ODEs. The obtained highly nonlinear sets of ODEs are then solved analytically by using the HAM procedure. The calculations of the thermal radiation term in the energy equation are done based on the Roseland approximation. The result of various embedded variables on temperature and velocity profiles is drawn and explained briefly. Aside from that, the numerical solution of well-known physical quantities, like skin frictions and the Nusselt number, is computed by means of tables for the modification of the relevant parameter. The analysis shows that the magnetic field has opposite behavior on and profiles. It is seen that more magnetic factor M decline and upsurge . Moreover, the behavior of skin friction and the Nusselt number are same for the magnetic parameter M. Meanwhile, a higher Reynolds number declines temperature profile and skin friction while upsurge the local Nusselt number. There are many applications of this study that are not limited to engineering and manufacturing, such as polymer industry, crystal growth, tumor therapy, plasma, fusing metal in electric heaters, nuclear reactors, asthma treatment, gastric medication, cooling of atomic systems, electrolytic biomedicine, helical coil heat exchangers, axial fan design, polymer industry, plane counter jets, and solar collectors.

Computational Analysis of Thermal Performance Augmentation in Helical Coil Heat Exchangers via CuO/Water Nanofluid

Computational Analysis of Thermal Performance Augmentation in Helical Coil Heat Exchangers via CuO/Water Nanofluid