Thermal-hydraulic Performance Parameters Research Articles

Experimental investigation and performance prediction of SAH using different arc rib roughness geometries – A comparative study

This study aims to investigate and compare the thermal performance of a solar air heater using a passive technique to enhance heat transfer between the absorber plate and the flowing fluid. The technique involves generating turbulence near the heat transferring surface through the use of artificial rib roughness. The study focuses on two different novel roughness geome-tries: full symmetrical arc rib roughness and half symmetrical arc rib roughness. By introducing additional gaps and varying the number of gaps in the roughness geometries, the study examines their effects on the solar air heaters thermal performance. The artificially roughened surface creates different turbulent zones, which are essential to the development of different types of turbulence in the vicinity of the heat transferring surface. The study finds that an optimal escalation in Nusselt number and friction factor by 2.36 and 3.45 times, respectively, occurs at certain gap numbers as 6 and ng as 5 for full symmetrical arc rib roughness. The maximum thermal-hydraulic performance parameter of 1.66 is attained at a Reynolds number of 6 000. The study also conducts correlation, mathematical modeling, and performance prediction under different operating circumstances.

Thermal performance analysis of corrugated plate solar air heater integrated with vortex generator

This research investigates the impact of vortex generators integrated with a corrugated absorber plate of solar air heater on the enhancement of heat transfer and thermal-hydraulic performance utilizing a 3D numerical model for Reynolds numbers varying from 7,000 to 25,000. Three different types of vortex generators (rectangular, trapezoidal, and delta) are investigated separately. Vortex generators in two pairs with various angles of attack of 15º, 30º, 45º, and 60º are mounted on the entrance section's upper wall of the domain of computation. The current numerical models are validated by comparisons with experimentally published data. The velocity vectors, turbulent kinetic energy, friction factor, Nusselt number, and thermal-hydraulic performance parameters are examined for the considered current cases considered. The numerical results demonstrate a significant impact of vortex generators on friction loss and transmission of heat. The values of thermal-hydraulic performance for utilizing a corrugated absorber plate integrated with vortex generators are found to be considerably higher than those for using a corrugated absorber plate alone. The highest value of the thermal-hydraulic performance parameter is 0.91 in the case of rectangular vortex generators at Re of 7000 and an angle of attack of 30º.

Turbulent flow-thermal-thermodynamic characteristics of a solar air heater with spiral fins

This work proposes a strategy by employing multiple spiral fins (SFs) for enhancing the low heat transfer rate of traditional smooth solar air heaters (SAHs). A numerical study involving the effects of the pitch ratio (P/Dh), quantity (N), and arrangement of SFs on fluid flow, heat transfer, and thermodynamic characteristics of the SAHs was conducted. The research findings indicated that the flow field was homogenized and the thermal boundary layer was weakened by inserting multiple SFs into the smooth SAH. This could increase the heat transfer rate by 30.63–137.51 % and decrease the overall entropy generation by 9.64–57.05 %, causing a 25.01–99.18 % improvement in thermodynamic efficiency. Reducing P/Dh and increasing N could improve the heat transfer rate, increase flow viscous entropy generation, reduce thermal entropy generation, and augment thermodynamic efficiency (ηⅡ). In addition, changing the rotation arrangement of the SFs from the counterclockwise to the counter-swirl improved the thermal-hydraulic performance parameter (THPP). Within the scope of this study, the SAH with P/Dh = 1.5 and N = 5 in a counter-swirl layout achieved the highest THPP of 1.04, and the SAH with P/Dh = 0.6 and N = 5 in an anticlockwise arrangement yielded the lowest entropy generation ratio of 0.43 and the maximum ηⅡ of 18.16 %.

A comprehensive review on the effect of turbulence promoters on heat transfer augmentation of solar air heater and the evaluation of thermo-hydraulic performance using metaheuristic optimization algorithms

AbstractSolar air heaters are characterized by poor thermal performance due to limited heat transfer capability of air, thereby necessitating the need for design modifications. Among a different system performance augmentation technique, turbulence promotors are widely used owing to its effectiveness. Based on design parameters such as geometry, size, pitch and arrangement of turbulence promoters, varying levels of heat transfer increment with the pressure drop penalty is achievable. This led to the development of new designs which could offer on optimum thermo-hydraulic performance for a wide range of Reynolds number. Such research invariably requires a thorough insight of data related to various design parameters and optimal thermal–hydraulic performance range. This article provides a detailed overview of various turbulence promotor designs and their optimal thermal–hydraulic performance ranges compiled from a wide spectrum of experimental and numerical studies. Apart from outlining the general flow characteristics of each turbulator design, this study also evaluates different metaheuristic optimization algorithm such as bonobo optimization (BO), particle swarm optimization and teaching–learning-based optimization algorithm for enhancing the thermal–hydraulic performance parameter (THPP). The study shows that the BO algorithm does not exhibit local trapping due to its self-adapting nature of the optimized parameters which makes it a promising choice for THPP optimization studies in air heater applications. The extensive review also shows that the arrangement pattern of rib turbulator plays a key role in thermo-hydraulic performance augmentation. Based on the BO optimization analysis, the range of THPP is determined for the optimized geometry of turbulence promoters. In the pool of rib design, transverse prism rib, multi-V-rib, multi-V-shaped rib with staggered rib, sinewave-shaped rib with gap and S-shaped ribs exhibits an optimal THPP range of 2.05–3.32, 2.43–2.94, 3.00–3.61, 1.58–3.40 and 2.05–3.74, respectively. Other turbulence promotor designs such as winglet vortex generator, dimple protrusion in arc shape and multi-V-baffles exhibits optimal THPP range of 1.95–2.2, 2.44–3.68 and 1.75–2.01, respectively. At the end, the study proposes key research gaps such as the use of combined ribs and vortex generators and discrete fin arrays of different geometry as future scope of research. Graphical abstract

THERMAL ANALYSIS OF A PLATE HEAT EXCHANGER (PHE) FITTED WITH CARDING TOOL PATTERNS USING CFD MODELING

Inspired by the wool carding tools, a new plate heat exchanger (PHE) design was developed, tested, and analyzed numerically. The present research work used computational fluid dynamics (CFD) simulations to examine the impact of various parameters, such as the rib type (continuous and discrete), the arrangement type (rectangular, square, and triangular), and the geometrical parameters (transversal and longitudinal pitches) on the PHE hydraulic and thermal performances. A three-dimensional (3D) evaluation of turbulent flow over a plate fitted with carding tool patterns was conducted using the<i> k-ε </i>turbulence model within the Reynolds number range from 400 to 1800. The numerical results were compared to previous experimental research to validate the dependability of the technique, and a mesh independence analysis was performed to confirm the precision and the accuracy of the CFD method. The results show that CFD ANSYS software can effectively predict the pressure drop across the carding tools and provide valuable insights into the fluid flow behavior within the system in terms of calculating the thermal hydraulic performance parameter (THPP) and the thermal effectiveness <i>ε </i>. The ultimate goal of this research work was to identify the ideal arrangement with the highest heat transfer rate and the lowest pressure losses in terms of determining the best THPP. Compared to the conventional chevron-type PHE, the thermal performance of the novel PHE design was enhanced by 25.63% and 47% in terms of nondimensional parameters e and THPP, respectively.

Employment of roughened absorber palate and jet nozzles with different hole shapes for performance boost of solar-air-heaters

In this study, roughened absorber plate and jet nozzle are simultaneously employed to enhance the efficiency of a solar based air heater. The impact of jet nozzle hole shape is comprehensively investigated for the mentioned system which have not been investigated before. Three-dimensional steady-state simulations of incompressible turbulent fluid flow and heat transfer are performed using the Reynolds-Averaged Navier-Stokes (RANS) equations to model the jet solar air heater (JSAH). Five different jet hole shapes (circular, triangular, square, hexagonal, and rectangular) are examined and results are compared with conventional structure. The thermal and hydraulic performance of the JSAH is assessed using a variety of geometric and operating parameters, including jet diameter ratio (dj/Dh), jet hole streamwise pitch (Lj/Dh), and Re number (Re). The results show that the ratio of (Nu/Nus) initially increases and then decreases as the hydraulic diameter of the jet holes increases. Circular jet holes consistently outperform other shapes, while rectangular and triangular jet holes perform poorly. The pressure penalty (f/fs) decreases with increasing (dj/Dh), with circular jet holes exhibiting the lowest value. Increasing the Reynolds number enhances heat transfer and pumping power but leads to a decrease in (Nu/Nus) and negatively affects the THPP of the JSAH compared to a conventional smooth solar air heater. The study also reveals that the THPP initially increases with streamwise pitch (Lj/Dh) but then declines, following the trend of (Nu/Nus). The results demonstrate up to 4.5 times higher Nusselt numbers with a jet solar air heater versus a smooth solar heater. A maximum thermal-hydraulic performance parameter of 1.64 indicates the proposed design's efficacy. This research furnishes critical insights into optimizing solar air heater performance by examining jet nozzle hole shape, streamwise pitch, and Reynolds number. It enables enhancing thermal efficiency and thermo-hydraulic performance.

Experimental analysis of heat exchanger using perforated conical rings, twisted tape inserts and CuO/H2O nanofluids

This research paper presents an experimental analysis on a heat exchanger tube using a newly designed perforated conical ring combined with twisted tape as inserts. The investigation analyzes various geometric and flow parameters in the experimental setup, including a wide range of Reynolds numbers, varying from 6000 to 30000, nanoparticle volume concentration (φnp) of 0.25-1.0%, the ratio of inlet flow dia to inner print dia of the ring (DIR/DBR) of 1.33-2.33, ring pitch ratio (RP/ DED) of 1.41-2.51, twist ratio (TL/ WT) of 3.33-4.38, with fixed values for other parameters: relative ring height ((DED/ WR) of 2.33 and nanoparticle diameter (dnp) of 30 nm. The optimal result of the thermal-hydraulic performance parameter (ηTT) is 1.45 at DIR/DBR = 1.83, TL/ WT = 3.50 and RP/ DED = 1.76. For the CuO/H2O nanofluids flow heat exchanger tube with perforated conical rings, empirical correlations were developed for the Nusselt number and the friction factor. These correlations were established with a range of 9.0% and 8.0%, respectively.

Emitting Electrodes Effect on the Enhancement of Heat Transfer by a Two Stage Electrohydrodynamic Gas Pump

In this study, emitting electrodes effect on the enhancement of heat transfer by a two stage electrohydrodynamic (EHD) gas pump is numerically analyzed. This study is implemented for a two stage EHD gas pump with 24 emitting electrodes configuration and the results are compared with 8 and 56 emitting electrodes configurations. The EHD gas pump is evaluated for a wide range of operating voltages starting from 20 kV up to 28 kV and wide range of Reynolds numbers (Re). The Reynolds numbers considered in this study varies in a range between 100 and 2000. At Re = 100, a maximum increase of 42% in the average Nusselt number is achieved with an applied voltage of 28 kV. The overall effectiveness of the EHD gas pump in heat transfer enhancement is evaluated by the thermal hydraulic performance parameter, (Nu/Nu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> )/(f/f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ), which is always greater than unity. EHD technique has a great potential.

Effect of Dimpled Rib with Arc Pattern on Hydrothermal Characteristics of Al2O3-H2O Nanofluid Flow in a Square Duct

The present work is concerned with the experimental analysis of the thermal and hydraulic performance of Al2O3−H2O nanofluid flow in dimpled rib with arc pattern in a square duct. The Alumina nanofluid consists of nanoparticles having a size of 30 nm. Reynolds number Renum studied in the square duct range from 5000 to 26,000. The nanoparticle volume fraction (ϕnp) ranges from 1.5% to 4.5%, the ratio of dimpled-arc-rib-height to print-diameter HAD/Pd ranges from 0.533 to 1.133, the ratio of the dimpled-rib-pitch to rib height PAD/HAD range from 3.71 to 6.71 and dimpled arc angle (αAD) range from 35° to 65°. The Al2O3−H2O-based nanofluid flow values of Nusselt number Nurs and friction factor frs are higher in comparison to pure water. The dimpled ribs in the arc pattern significantly improved the thermal-hydraulic performance of the investigated test section. The nanoparticle concentration of 4.5%, the ratio of dimpled arc rib height to print diameter of 0.933, the relative dimpled arc rib height of 4.64 and the dimpled arc angle of 55° deliver the maximum magnitude of the heat transfer rate. The maximum value of the thermal-hydraulic performance parameters was found to be 1.23 for Al2O3−H2O-based nanofluid flow in a dimpled rib with arc pattern square duct for the range of parameters investigated. Correlations of Nurs, frs and ηrs have been developed for the selected range of operating and geometric parameters.

Feasibility of Low-Enriched Uranium Fueled Nuclear Thermal Propulsion in the Low-Thrust Region Below 16klbf

This paper establishes the feasibility of Low-Enriched Uranium fueled Nuclear Thermal Propulsion (LEU-NTP)reactors in the low-thrust region below 16klbf (71kN). A reference, 7.5klbf, High-Enriched Uranium (HEU) design is converted to 19.75% enriched LEU and shown to be capable of reaching criticality and meeting other performance requirements with a minimalmass increase. At this smaller scale, historical LEU-NTP conversion techniques that focus on maximizing neutron moderation or minimizing leakage within the active core are insufficient. Thus, the 7.5klbf preliminary design requires several unique modifications, including a reduction in the number of control drums and adjustments to selected materials. To verify the design’s feasibility, several keyneutronic and thermal-hydraulic performance parameters including burnup, Xenon worth, and submersion criticality are characterized with Serpent 2.0 and the Space Propulsion Optimization Code. The methods applied in this workreveal an opportunity for further LEU-NTP optimizationthat may directly translate to increased scalability and efficiency for future designs.

Numerical investigation of the thermal-hydraulic characteristics of turbulent flow in conical tubes with dimples

Innovative designs of heat exchangers are crucial to increase the heat transfer effectiveness for the purpose of compactness, energy savings, and emission reductions, among others. In this paper, the thermal-hydraulic performance of turbulent flow inside dimpled and conical tubes under a constant heat flux of 40 kW/m 2 is numerically investigated using Ansys-Fluent. The proposed novel design and the associated performance analysis were not covered before in the specialized research works of the related literature. Different geometrical and operational parameters (tube diameter ratio/flow modes) are varied to generate key performance indices for the dimpled and conical configurations compared to the traditional smooth heat exchanger case. The model was well-validated against both cases of dimpled and smooth tube configurations. Thermal-hydraulic performance parameters, mainly Nusselt number and friction factor, and performance evaluation criteria (PEC) are investigated for different diameter ratios (DR) of various conical tube heat exchangers of smooth and dimpled surfaces within a range of Reynolds number from 3000 to 40,000. The results for conical tubes with dimples showed considerable enhancements in heat transfer and the overall thermal-hydraulic performance compared to traditional smooth geometrical configurations. The study showed that convergent tube with dimples (DR = 1.5) presents the maximum value of PEC with 29.54% enhancement compared to the smooth geometry with DR = 1. The average-values of PEC over the whole studied range of Re with 8.03% enhancement compared to the smooth geometry at DR = 1, of all studied cases. In addition, convergent tube with dimples (DR = 1.5) presents a maximum percentage of the increase in Nusselt number ratio Nu r (2.72 at Re = 3000) with 121.4% enhancement compared to the corresponding smooth one. Hence, it can be considered as a promising technique in terms of energy-saving, especially at low values of Reynolds number. It can also be deduced that the newly proposed design of convergent tube HEX with dimples has positive energy efficiency operational characteristics and environmental impacts in terms of potential CO 2 reductions.

Investigations of heat transfer and flow characteristics of wall-bounded jets on a sinusoidal wavy surface

Turbulent wall-bounded jets are used in various practical engineering and industrial applications, including cooing of electronics devices, heat exchange systems, and cooling of gas turbine blades. The aim of the present computational study is to investigate an enhancement in heat transfer using different wall-bounded jets. Detailed discussions on the effect of the amplitude of the wavy surface and offset ratio are provided. The offset ratio varies from 0 to 5.0, where the value of zero represents a turbulent wall jet. The amplitude of sinusoidal wall is ranging from 0.1 to 0.8. The computed results are validated with the reported experimental results. The validation shows that among four turbulence models used, namely, renormalization group k-ϵ (RNG), realizable k-ϵ, standard k-ω and shear-stress transport k-ω (SST), the latter provides a good agreement with the experimental results. The position of the offset ratio and amplitude of the wavy surface affect the heat transfer enhancement. An enhanced heat transfer of 29.46% for turbulent wall jet is achieved for the amplitude of 0.8. The thermal-hydraulic performance (THP) increases for the wall jet by approximately 15% for the maximum amplitude considered. The axial position of the reattachment length and primary vortex centre increase with amplitude. Correlations are developed for the average Nusselt number, vortex centre, reattachment point, and thermal-hydraulic performance parameter with the amplitude of the sinusoidal wall.

Energy efficiency and transient-steady state performance comparison of a resistance infant incubator and an improved thermoelectric infant incubator

The present study aims to contribute energy related research by comparing thermal hydraulic performance parameters including energy consumptions, set temperature precisions and noise levels of newly improved thermoelectric infant incubator having thermoelectric heat pump and existing resistance infant incubator. For that purpose, an experimental set-up has been established and equipped with necessary measuring instruments and control units which allow determination of the above-mentioned performance parameters in transient and steady state operation mode of both infant incubators. According to the experimental results, the thermoelectric system was able to control the mean temperature of the hood with a precision of 0.05 °C while precision of the resistance system was 0.1 °C. Since incubators are generally used in heating operation mode, the coefficient of performance (COPheating) value of the thermoelectric system in the steady state condition where the mean hood air temperature is 36 °C and the ambient temperature is 25 °C, which is around 1.4, was higher than the resistance system. Thanks to the cooling mode of the improved thermoelectric system, it was shown that transient period can be shortened for lower set temperatures without opening the hood and operate in high ambient temperature (30 °C and above) environments and in transport incubators.

Heat transfer and performance analysis of SAH having new transverse finned absorber of lateral gaps and central holes

An experimental work is presented on the performance of solar air heater (SAH) has new designed absorber of finned transverse plate of lateral gaps and central holes. Moreover, a complete heat transfer analysis of the radiation and convection and SAH thermal performance are presented and discussed. The performance of this transverse SAH (TR_SAH) is compared with identical conventional flat plate SAH (FP_SAH) for single (SP) and double-pass (DP) airflow and air mass flow rates (AMFR) of 0.025, 0.05, and 0.075 kg/s. The experimental study is performed under hot climate conditions of Upper Egypt. The findings show that for all studied cases, TR_SAH has higher energy gain, output air temperature, thermal efficiency, and Nusselt number on the absorber plate, thermal-hydraulic performance parameter, and pressure drop compared to FP_SAH. The energy loss and radiation and convection Nusselt number on the TR_SAH glass plate is lower than that of FP_SAH. The maximum TR_SAH energy efficiency of value of about 89% is achieved in the case of DP airflow and high AMFR of 0.075 kg/s, with an enhancement of 24.2% compared to FP_SAH. The higher TR_SAH efficiency at these conditions reflects the optimal TR_SAH absorber design especially at high AMFR and using DP airflow. Despite TR_SAH air pumping power is greater than FP_SAH but it has a negligible effect on net energy gain.

Investigation on heat transfer enhancement in a circular pipe with artificial roughness

This paper presents a numerical analysis of convective heat transfer enhancement of transverse ribs in circular tubes. Several CFD simulations are carried out for turbulent airflow to analyze heat transfer and pressure drop provided with transverse rectangular ribs. The rib height and pitch are widely varied along with the flow Reynolds number. The effect of each parameter is examined and discussed. To accurately predict major parameters (Nusselt number, friction factor, and thermal hydraulic performance parameter) a deep neural network is developed, trained, and tested by current CFD data. The result demonstrates that artificial neural network shows better performance compared to other methods of prediction (e.g. power-law approximation) and can offer an economical and powerful approach for modeling optimal heat enhancement parameters.

Numerical investigation on the performance of a solar air heater using jet impingement with absorber plate

Solar air heater is the simplest heating device for utilizing solar thermal energy. Jet impingement technique can be used to amplify the performance of a solar air heater by increasing the heat transfer between fluid and heated surface. Under the present study, an attempt has been made to carry out a numerical investigation on heat transfer behaviour of a solar air heater having absorber plate with impinging jet. 3D-Computational fluid dynamics (CFD) simulation using ANSYS-18.1 has been carried out with RNG k–ɛ turbulence model, and the upwind scheme is applied for the discretization of governing equations. Jet diameter ratio and jet height ratio are the considered system parameters, and their considered ranges are 0.065 to 0.195 and 0 to 0.433, respectively. The performance of solar air heater with jet impingement is investigated under different flow conditions taking Reynolds number ranging from 3500 to 17,500. It has been found that a significant increase in heat transfer for jet impinging solar air heaters is achieved in comparison to smooth solar air heater under similar operating conditions. The maximum heat transfer enhancement of 7.58 with a friction factor penalty of 9.01 times is obtained at jet diameter ratio of 0.0650 and jet height ratio of 0.216 for Reynolds number of 17,500. Maximum thermal-hydraulic performance parameter value of 3.66 is obtained correspond to jet height ratio of 0.216 and jet diameter ratio of 0.065 for Reynolds number of 15,500.

Performance investigation of a solar thermal collector provided with air jets impingement on multi V-shaped protrusion ribs absorber plate

In the present work, the heat transfer through a solar thermal collector (STC) provided with jet air impingement on the absorbent plate fitted with multi V-shaped protrusion ribs is investigated experimentally. The investigation is carried out for geometric parameters such as Relative width ratio (WPR/WAPR), Relative protrusion rib height (hPR/dPR), Relative pitch ratio (PPR/hPR), Angle of attack (αPR) respectively. The values of the streamwise pitch ratio (XSW/dh) = 0.40, spanwise pitch ratio (YSW/dh) = 0.85 and jet diameter ratio (dj/dh) = 0.064 are kept constant. The overall performance of STC is effectively evaluated by varying Reynolds number (Re) in the range 2500–35,000. The results obtained from the experiments shows that the impingement jets flow on multi V-shaped protrusion ribs absorber plate accelerated the heat transfer through the solar collector channel. The optimal augmentation is obtained at WPR/WAPR= 5, hPR/dPR= 0.9, PPR/hPR = 8 and αPR = 65° respectively. Thermal-hydraulic performance parameter ( ηPR) has also been investigated and the maximum value of 3.44 is obtained for the range of parameters studied.

A two-level Plackett-Burman non-geometric experimental design for main and two factor interaction sensitivity analysis of zigzag-channel PCHEs

Supercritical carbon dioxide (sCO2) is currently being studied as the working fluid in producing power using the Brayton cycle due to its excellent physical and thermodynamic properties, especially near the critical point. Printed circuit heat exchangers (PCHEs) are being considered for use as condensers and recuperators for this purpose due to their high strength and compact designs. This paper examines the sensitivity of the Nusselt number (Nu), Colburn factor (j), and Fanning friction factor (f) for zigzag-channel PCHEs to 20 geometric design factors and operating conditions. A two-level Plackett-Burman, non-geometric resolution III experimental design with no replications was used. This experimental design was then folded over to produce a resolution IV design to eliminate confounding of main factor effects. Main factor and two factor interaction effects were examined. Computational fluid dynamics (CFD) was used to simulate each tested case. Data indicates that zigzag-channel PCHE thermal-hydraulic performance parameters are most sensitive to changes in channel bend angle, bend angle radius of curvature, mass flow rate, and channel width. Additionally, some two factor interactions of the more significant main factors were found to be of importance.

Performance evaluation of a novel solar air heater with arched absorber plate

The study presents a performance evaluation of a novel solar air heating system with arched absorber plate using turbulators. Simulation work is carried out in ANSYS FLUENT (v16.2) platform with RNG k-ε turbulence model at constant heat flux (500 W m−2), in order to compare the thermal-hydraulic performance of the proposed design for a range of Reynolds number (3800–14000). Performance of the solar air heater is projected in the terms of Nusselt number (Nu), frictional factor (Fr) and thermal-hydraulic performance parameter (THPP). It is observed that the arched absorber plate design increases the air turbulence and vortex generation, which results in reducing laminar sub-layer generation near the surface of the absorber plate. A significant improvement is observed in Nusselt number at high Reynolds Number (above 10000). However, a marginal enhancement is also observed in frictional factor due to providing an extra obstacle along the duct length with arched shaped design in the flow field. It is observed that arched shape design of absorber plate can significantly improve overall performance of the solar air heating system using various turbulators. This study will likewise provide a new direction to the work trend in this area.

Experimental study of enhancement of heat transfer and pressure drop in a solar air channel with discretized broken V-pattern baffle

This article presents an experimental study on heat transfer and friction characteristics of solar air channel fitted with discretized broken V-pattern baffle on the heated plate. The effect of geometrical parameters, predominantly the gap width and gap location has been investigated. The roughened baffle air channel has a width to height ratio, W/H of 10. The relative baffle gap distance, Dd/Lv and relative baffle gap width, gw/Hb has been varied from 0.26 to 0.83 and 0.5–1.5, respectively. Experiments have been carried out for the range of Reynolds number, Re from 3000 to 21,000 with the relative baffle height, Hb/H range of 0.25–0.80, relative baffle pitch, Pb/H range of 0.5–2.5; and angle of attack, αa range of 30°–70°. The optimal values of geometrical parameters of roughness have been obtained and discussed. For Nurs the greatest enhancement of the order of 4.47 times of the corresponding data of the without channel has been obtained. The absolute highest data of thermal hydraulic performance parameter has been found to be greater corresponding to Dd/Lv of 0.67, gw/Hb of 1.0, Hb/H of 0.50, Pb/H of 1.5, and αa of 60°. The maximum value of the thermal hydraulic performance parameter was found to be 3.14 for the range of parameters investigated.