Pitch Ratio Research Articles

Thermo-fluid characteristics and exergy analysis of a twisted tube helical coil.

In the present investigation, the exergy of an innovative technique involving the integration of curved helical tubes with twisted passages was experimentally presented. This technique aims to improve the thermofluid characteristics by involving the swirl intensity of fluid flow in a twisted tube helical coil (TTHC). Six identical geometries with different pitch ratios Υ of 36mm, 54mm, and ∞ (smooth/no twisted) were experimentally explored at two different inner tube profiles of triangular and square cross-sections in counter flow arrangements. The experimental runs were carried out at 10,300 ≤ Rei ≤ 37,800 and 2400 ≤ Reo ≤17,600 for both the inner and annulus fluids, respectively. The results showed that the Nusselt number, Nu, increased by 39.6% and 41.5% for triangular and square inner twisted cross-section profiles, respectively, at a [Formula: see text] of 36mm at the expense of increasing f by 37.6% and 60.7%, respectively. The results also showed that the thermal performance factor reached 1.3 and 1.25 for a [Formula: see text] of 36mm for the triangular and square inner twisted tube profiles, respectively. A comprehensive study is performed to analyze the TTHC from thermal, frictional, and exergetic viewpoints. New correlations for expecting the annulus Nuo and fo are presented.

Thermal performance enhancement of laminar flow using compound twisted square duct and variable pitch twisted tape inserts

This study involves a computational analysis to find the effectiveness of incorporating twisted tape within a twisted square duct for improving heat transfer, focusing on laminar single-phase flow. The primary goal is to study how varying the tape pitch (y) influences the hydrothermal performance of this system. The twisted square duct pitch (S) and twist ratio (H) were kept constant. The numerical analysis is performed under conditions of uniform wall temperature, and varying the pitch ratio (y/S) across values of 0.25, 0.5,0.75, 1, 1.25, 1.5 and 1.75. The obtained findings suggest that the addition of twisted tape within the twisted square duct results in a greater rate of heat exchange and pressure drop relative to the simple twisted square duct. Research reveals that despite a higher rate of heat transfer for a pitch ratio of 0.25 the increased friction factor results in less effective thermal performance compared to the cases with pitch ratios of 0.75 and 0.5. The thermal performance factor reaches its peak at 1.32, corresponding to the Reynolds number 1000 for a pitch ratio of 0.75 case. Conversely, the lowest thermal performance factor value of 0.89 is observed at the Reynolds number 500 for pitch ratio 1.25 case.

Multi-physical field coupling effect in micro pin-fin channel cooling with coaxial-like through-silicon via (TSV) for three-dimensional integrated chip (3D-IC)

Through-silicon via (TSV) technology offers significant advantages for three-dimensional integrated chip (3D-IC) by enabling higher integration densities and faster signal transmission rates. The increased power density of 3D-IC poses substantial thermal management challenges. Microchannel cooling is widely used for chip-level thermal management. However, the balance of heat dissipation and signal integrity between layers of 3D-IC with TSV remains elusive. This work presents a study on the electrical-thermal-force-flow-solid multi-physics field coupling effect of micro pin–fin channel cooling systems embedded with coaxial-like TSVs in 3D-IC, aiming to optimize signal integrity and thermal performance. We analyze the structural parameters of coaxial-like TSVs, such as TSV aspect ratio and pitch ratio, focusing on their impact on signal shielding efficiency and thermal conductivity. The results show that a coaxial-like TSV structure with an aspect ratio of 15 and a pitch ratio of 2.5 reduces the maximum temperature and insertion loss by 3.97% and 3.60%, respectively. This structure is then embedded in a micro pin–fin channel to explore the effect of pin–fin arrangement on heat dissipation at different Reynolds numbers. Using multi-objective optimization through response surface methodology (RSM) and the non-dominated sorting genetic algorithm II (NSGA-II), we obtain a series of optimal solutions for TSV-embedded micro pin–fin. When the weights of heat transfer and pressure drop are balanced, the average Nusselt number increases by 6.8% with a 2% rise in pressure drop. These findings provide valuable insights for the design and optimization of high-performance 3D-IC cooling systems.

Inner–outer interaction of unsteady turbulent flow inside duct with wall corrugations: Augmentation and saturation

This study investigates the inner–outer interaction of the unsteady turbulent flow inside a duct with wall corrugations, where “inner” refers to the trapped flow in a corrugation-induced cavity array and “outer” relates to the mainstream flow transporting through a circular duct. Configurations with different pitch–diameter ratios (P/D) are used to demonstrate the effect of the cavity flow pattern on the mainstream flow variations. An improved delayed detached-eddy simulation with dynamic blending function is performed to acquire high-fidelity turbulent flow data, in which dynamic evolution of multi-scale vortex structures containing hairpin vortices and vortex fragments is clearly resolved. The subsequent statistical analysis reveals a nonlinear variation tendency of the inner–outer interaction intensity, experiencing sudden augmentation first and then a gradual attenuation toward the final saturation. Comparatively, a larger pitch ratio results in a stronger interaction under the effect of bicentric recirculation zones within the cavity array. Moreover, a proper orthogonal decomposition analysis allows for the visualization of energetic flow structures, as consistent velocity variations throughout the duct volume are identified for a larger pitch ratio, while discontinuity at the duct termination is found for a smaller pitch ratio. Finally, an advanced elliptical model based on the spatiotemporal cross correlation analysis is proposed to examine the convection velocity and sweeping velocity of the interactive mainstream flow and cavity flow. The results highlighted the presence of first-augmented and then saturated dynamics and kinematics inside the duct with the cavity array.

Numerical investigation on the thermohydraulic performance of a solar air heater duct featuring parabolic rib turbulators on the absorber plate

Solar power is a clean and sustainable energy option, widely accessible and capable of driving the creation of more sustainable systems in the future. A specialized device called the Solar Air Heater harnesses solar energy for various applications. In the current study, a novel quadratic shape ribs affixed to the absorber plate in different orientations with a transverse pattern to the flow, and one straight side and one curved side are subjected to a compressive analysis using numerical methods. The two rib orientations are shown individually, with one side being straight and the other quadratic curve. Ansys Fluent is used to examine the impacts of a number of variables on SAH performance, including rib characteristics (pitch and height) and airflow inlet velocity. The range of Reynolds numbers used for the investigation is 3400–20000, with a rib pitch ratio ranging from 6.66 to 20. The contours of pressure, temperature, and velocity are displayed to elucidate the physics of fluid flow and heat transfer. A notable enhancement is achieved, wherein an optimized case with parabolic rib turbulator SAH and rib roughness pitch of 16.66 yields a Thermal Enhancement Ratio (TER) of 2.14.

Research on the Arrangement Scheme of Spirally Twisted Tape Inserts in a Grate Furnace

To eliminate the flow dead zone and homogenize the asymmetric flow field of a grate furnace, spirally twisted tape inserts (STTIs) with a pitch ratio of 1.5 were installed in the vertical flues of an SCL1000-13.5/450 grate boiler. The arrangement schemes found to be present inside the chosen 1000 t/d grate furnace, determined using the orthogonal experimental method, included separate installation in chamber II, separate placement in chamber III, and simultaneous arrangement in both chamber II and chamber III. The effects of row spacing H, column spacing W, and mounting angle φ were investigated by means of the practicable and feasible numerical simulation method. With a focus on the uniformity degree of the flue gas, the results showed that temperature distribution is directly correlated with the velocity field. When it comes to the uniformity of the flow field, the exclusive use of STTIs in chamber II was better than that in chamber III. Under the optimal combination scheme of STTIs in both chamber II and chamber III (scheme N323), the exhaust gas temperature reached the minimum value and the uniformity index of temperature increased to the range of 0.994~0.997. The findings in this work could provide a reference for the optimization of the flow field in a grate furnace.

Influence of submerged impingement jet designs on solar air collector performance

The present study experimentally investigates the solar air heater performance employing submerged impinging jets (SAHSIJ). The submerged jets produce high flow velocities, leading to significant turbulence aided by shear forces at the heated surface, resulting in increased and evenly distributed heat removal rates. The study explores the impact of geometric parameters viz jet spacing ratio (Sj/Dh) from 0.108 to 0.433, jet angles (α) from 75° to 90° jet diameter ratio (d/Dh) from 0.043 to 0.076, span-wise pitch ratio (Y/Dh) from 0.43 to 1.08 and stream wise pitch (X/Dh) from 0.43 to 1.73 on the Nusselt number and friction performance to enhance the overall efficacy of the system. To evaluate the effectiveness of the new SAHSIJ design in terms of thermal and thermo-hydraulic performance, the results are compared with those from a smooth duct solar air heater. The results show that the novel solar air heater with submerged pipe jet significantly outperforms the smooth duct solar air heater in terms of heat removal from the absorber plate. SAHSIJ achieved a thermal efficiency (ηth) of 75.3 % and a thermo-hydraulic efficiency (ηeff) of 69.2 %, with a thermo-hydraulic performance parameter (η) of 3.19.

Study on nonlinear coupled dynamic response of the integrated polar ocean nuclear energy platform

An integrated polar ocean nuclear energy platform is capable of providing adequate electrical and thermal energy essential for polar oceanic development activities. Precisely forecasting the platform's motion response within the marine environment is pivotal for the assurance of its safety. A scenario where the natural frequencies of heave, roll, and pitch of such an integrated polar ocean nuclear energy platform align closely to a 2:1:1 ratio, and when the wave frequency nearly matches the aggregate of the platform's natural heave and pitch frequencies, could induce a phenomenon known as sum-type nonlinear internal resonance. This phenomenon can significantly amplify the swing (roll or pitch) motion of the platform, posing a grave risk to both personnel and equipment onboard. Investigating these nonlinear internal resonance phenomena within the nuclear energy platform is critical for informing both the design and practical deployment of these platforms. Following the validation of the numerical simulation against experimental results, a detailed analysis of sum-type nonlinear internal resonance phenomena in the integrated polar ocean nuclear energy platform under regular wave conditions was performed using a combination of numerical simulations and nonlinear dynamics theory. It was observed that upon exceeding a certain wave height threshold, the platform enters a state of sum-type nonlinear internal resonance, engendering highly complex motion patterns. Notably, irrespective of initial conditions, this resonance triggers the roll motion of the platform, facilitating the external dissipation of energy in a half-sub-harmonic vibration manner. Increasing damping can effectively suppress the occurrence of nonlinear internal resonance phenomena in the platform. In designing the integrated polar ocean nuclear energy platform, it's crucial to avoid having the natural frequency ratios of heave, pitch, and roll align as 2:1:1. If unavoidable, adding side plates to increase damping can mitigate the effects of sum-type nonlinear internal resonance.

Thermal Performance of a Laminar Flow Double Pipe Heat Exchanger with Spiral Airfoil Inserts

Objective: This study evaluates the thermal performance of a double-pipe heat exchanger using a spiral airfoil insert in the inner pipe. Methods: The enhancement technique is classified as a passive method, as it does not require the direct application of external power to improve the heat transfer coefficient. Spiral pitch ratios of P/D=7, 5, and 3 were used, with the Reynolds number (Re) varying within the laminar flow regime (Re ≤ 2,100). Cold water flows inside the inner pipe, while hot water flows counter to it in the annulus. Results: The experimental results show that the Nusselt number increased by 159%, 161%, and 171%, respectively, compared to a smooth pipe alone, for flow rates of 2L/min, 2.5L/min, and 3L/min. Additionally, the highest friction factor reached 142%. Conclusion: The results indicate that the best performance evaluation criterion (PEC) was achieved within the flow range of 2L/min to 3L/min, with a pitch insertion of 3, yielding a PEC of 158% to 152%, respectively.

Thermal performance augmentation of microchannel using curved rectangular winglet vortex generators having rectangular perforation

This article innovatively introduces the application of punched curved rectangular wing vortex generators positioned on opposing sides of a rectangular microchannel. Through a comprehensive approach combining numerical simulations and experimental investigations, the flow dynamics and heat transfer performance of these VGs under turbulent conditions are thoroughly examined. This analysis is performed in the turbulent flow regime, specifically at Reynolds number ranging from 2500 to 3500. The governing equations are solved by using SST k-ω model. To evaluate the behavior of mixed vortices, a range of key metrics is utilized, including the Nusselt number ratio, friction coefficient ratio, and thermal enhancement factor (TEF). The study encompasses variations in opening angles (θ = 0°, 5°, 10°, 15°) and pitch ratios (PR = P/H = 15, 30, 45) to determine their impact on the overall system performance. The findings reveal that the punched curved rectangular winglet VGs effectively induce mixed vortices, leading to an enhancement in local heat transfer rates. However, the presence of fluid jets hinders the formation of other vortices. Compared to a smooth tube, the maximum TEF also experiences a 26 % rise. To validate the findings, the field synergy principle and entropy generation theory was utilized.

Enhancing heat transfer with a hybrid vortex generator combining delta wing and winglet designs: A numerical study using the GEKO turbulence model

This paper presents a numerical study on the enhancement of heat transfer in a solar air heater (SAH) duct with Hybrid Vortex Generators (HVG) placed periodically along the flow direction on its heated wall (absorber plate) for fluid flow and convection heat transfer at Reynolds numbers between 4121 and 25,365. HVGs consist of a trapezoidal winglet (TWL) for HVG-winglet-base-angles θ = 45° and 30°, or a combination of a delta winglet (DWL) with a delta wing (DWG) for angles θ = 26°, 18° and 12°. The angle of attack for the winglet (TWL or DWL) in the HVG is set at 30°, while the merging angle with the DWG is 45°, and the relative height BR = e/H = 0.48 remains constant. Initially, the effects on heat transfer and friction factor of Trapezoidal Winglet Vortex Generator (TWVG) and HVG45 (θ = 45°) obtained by basic modification on TWVG are investigated under the same flow conditions for PR = 1.5 and Re = 11,205. Subsequently, parametric studies are performed for five different HVG-winglet-base-angles (θ = 45°, 30°, 26°, 18° and 12°) and three different longitudinal pitch ratios (PR = PL/H = 1.0, 1.5 and 2.0). The calculations are performed with ANSYS Fluent 2021R2 based on the finite volume method. In order to model turbulent flow, the GEKO (GEneralized K-Omega) turbulence model recently developed by ANSYS and based on the k-ω formulation is used. HVG45, obtained by basic modification on TWVG, produces slightly stronger and more effective longitudinal vortices compared to TWVG, showing a 3.87 % decrease in friction factor and a 4.11 % increase in Nusselt number and thus a 5.43 % increase in Thermal Enhancement Factor (TEF). Parametric investigations are conducted across a range of values for both θ and PR. The highest rise in friction factor is attained at the lowest Reynolds number, reaching a value of f/f0 = 54.52, while the most significant enhancement in heat transfer rate is noted at the highest Reynolds number, with Nu/Nu0 = 5.86 for θ = 45° and PR = 1.0. The TEF reaches 2.42 at the lowest Reynolds number for the HVG18 with a winglet-base-angle of 18° and a longitudinal pitch ratio of 1.5. The resulting findings not only offers a new approach to improve the thermal performance of solar air heaters but also hints at the potential success of the GEKO model in predicting turbulent flow and heat transfer analysis.

Heat transfer analysis and melting behavior of nano composite phase change materials (NCPCMs) in a reverse flow solar air heater

This paper presents a CFD investigation on heat transfer analysis and melting behavior of Nanocomposite Phase Change Materials (NCPCMs) in a Reverse Flow Solar Air Heater (RFSAH). Semicircular tubes filled with PCM are embedded on the top surface of the absorber plate. The study was conducted with three different nanoparticles (CuO, Al2O3, Fe3O4) based NCPCMs at three concentrations of 0.1, 0.2, and 0.3 % by weight. The constant geometrical parameters such as pitch ratio (P/e = 6), height ratio (e/Dh=0.1571), and Reynolds number (Re = 5000) is considered for this study. A 2-D transient numerical analysis using the RNG k-ε turbulence model is performed for the melting behavior of NCPCMs inside the semicylindrical tubes. The incorporation of nanoparticles into the base PCM enhances thermal conductivity but reduces the latent heat of NCPCMs. Thus, it is observed that NCPCMs have a faster melting rate. The CuO based NCPCM shows a more quick and uniform phase transition compared to the Fe3O4, and Al2O3 based NCPCMs and reached their peak value at a higher mass fraction of 0.3. Furthermore, the heat transfer and melting fraction improves with increasing in mass fraction of nanoparticles. The phase transition process of CuO based NCPCM is approximately 1.9 times, and 1.01 times, 1.03 times faster as compared to the base PCM, and Fe3O4, Al2O3 based NCPCMs respectively.

Jet array impingement heat transfer in a rectangular cavity with effusion holes

Various researchers have studied jet array impingement heat transfer in impingement/effusion cooling systems. However, there is a lack of research on impingement/effusion cooling systems installed within rectangular cavities that focus on the impact of the proximity of the jet hole to the cavity sidewalls on cooling performance. The main objective of this study is to investigate the flow and heat transfer characteristics of jet array impingement with effusion holes in a rectangular cavity, considering various spacings between the cavity sidewalls and the outermost jet hole. The design parameters in this study include the ratio of the jet hole pitch to jet hole diameter of 7.1, 10.0, and 16.7, and the ratio of the distance between the jet and impingement plates to jet hole diameter of 2, 6, and 10, with the Reynolds number based on the jet hole diameter ranging from 2500 to 15,000. Heat transfer characteristics in the stagnation region and wall jet region were examined using local Nusselt number distributions on the impingement surface, measured by liquid crystal thermography. The local Nusselt number was high in the stagnation region and decreased radially from the stagnation region as the wall jet region formed. The closer the outermost jet hole is to the sidewall, the higher the Nusselt number on the impingement surface near the sidewall. Moreover, the flow structure in the rectangular cavity was numerically investigated, and the velocity vectors and streamlines showed that primary and secondary vortices were generated in the middle of two neighboring jets and near the sidewall, respectively. This study also assessed previous average Nusselt number correlations. Based on experimentally determined average Nusselt number data with 54 center unit cells and 1296 side unit cells, new correlations to predict the average Nusselt number on the impingement surface in a rectangular cavity with effusion holes were developed.

Heat Transfer and Fluid Flow Over A Bank of Longitudinally Finned Flat Tubes: A Numerical Study

This computational study investigates the heat transfer rate and fluid flow characteristics of a staggered arrangement of longitudinally finned flat tube banks ( ) with a constant surface temperature. The finite volume method ( ) is used to solve the governing equations using the commercial software . This study considers longitudinal pitch ratios ( ). In addition, the dimensionless transverse pitch ratio ( )=3 and both the dimensionless upstream fin length ratio ( )= ( ) =0.8 is the dimensionless fin angle . The focus of the investigation is a Reynolds number range between with constant physical properties. The analysis examines pressure drop, dimensionless heat transfer rate, and the average Nusselt number. Results indicate that as Reynolds numbers increase and dimensionless longitudinal pitch ratios decrease, the heat transfer rate between tube surfaces and airflow increases to reach maximum value of 275. In addition, the Reynolds number affects the pressure drop, Began number, average Nusselt number, and thermal hydraulic performance.

Flow over two inline rough cylinders in the postcritical regime

This study investigates the flow behavior over roughened inline cylinders for postcritical flow, a parameter space with relatively little prior scrutiny. Two cylinders of the same relative surface roughness, ks/D=1.9×10−3, separated by a pitch (i.e., L, distance between the centers of two cylinders) between 1.175≤L/D≤10 are studied at Reynolds numbers from 3×105 to 6×105 using unsteady surface pressure measurements. As pitch ratio is increased from L/D=1.175, CD of the downstream cylinder increases sharply at (L/D)c=3.25. This critical pitch ratio (L/D)c is toward the lower end of the reported range for subcritical smooth cylinders. Asymmetric mean gap flow along with alternating reattachment is found for 1.5≤L/D<2.25 (i.e., two asymmetric modes in the gap, mode 1 and mode 2, that are the reflections of each other), and symmetric gap flow with a continuous reattachment is found for 2.25<L/D≤3. The gap flow is also symmetric for the closest pitch ratio tested of L/D=1.175. While the change in upstream cylinder drag coefficient with Reynolds number broadly follows that of an isolated cylinder, for the downstream cylinder, it is approximately independent. The critical separation is also insensitive to Reynolds number within 3×105≤Re≤6×105. Transitions between the reattachment and the co-shedding flow are predominantly continuous over the spanwise planes tested. On the other hand, alternating reattachment occurs in spanwise cells, where one sectional measurement exhibits the asymmetric mode 1 while a spanwise-adjacent section exhibits the asymmetric mode 2 or even symmetric flow. Previously reported maxima in the fluctuating lift and drag coefficients of the downstream cylinder at L/D≈2.4 at subcritical Reynolds numbers are absent in the current investigation.

Thermo-fluid performance of axially perforated multiple rectangular flow deflector-type baffle plate in an tubular heat exchanger

The study investigated an unconventional heat exchanger design that utilizes swirling airflow to enhance heat transfer over heated tubes. This innovative system incorporates a perforated round baffle plate, accompanied by multiple rectangular air deflectors oriented in opposite directions at varying inclination angles. These deflectors are symmetrically arranged at different pitch ratios alongside consistently spaced tubes forming a circular configuration, all subject to a uniform heat flux. Enclosed within a circular duct with longitudinal airflow, the combined baffle plate and tube assembly bring forth efficient heat transfer. The air-side turbulence intensified by the deflectors induces a chaotic motion, contributing to enhanced surface heat transfer. Each baffle plate has twelve opposite-oriented deflectors, resulting in opposing swirl flows that further promote flow recirculation and augment surface heat transfer. The performance of this heat exchanger was evaluated by considering different pitch ratios and inclination angles across a Reynolds number range of 16000-30000. The findings demonstrate that the heat exchanger with rectangular flow deflectors on the baffle plate exhibits significant improvements in thermo-fluid performance. Notably, an average enhancement of 1.88 was observed at an inclination angle of 50 degrees and a pitch ratio of 1.2 when compared to an exchanger without baffle plates, emphasizing the considerable impact of these design aspects.

Experimental investigations on thermo-fluid performance of perforated baffle aided with oppositely oriented sawtooth deflector in tubular heat exchanger

Purpose The investigation concentrated on studying a distinct category of tubular heat exchanger that uses swirling airflow over tube bundle maintained at constant heat flux. Swirl flow is achieved using a novel perforated baffle plate with rectangular openings and multiple adjustable opposite-oriented saw-tooth flow deflectors. These deflectors were strategically placed at the inlet of the heat exchanger to create a swirling flow downstream. Design/methodology/approach The custom-built axial flow heat exchanger consists of three baffle plates arranged longitudinally supporting tube bundle maintained at constant heat flux. The baffle plate equipped with saw-tooth flow deflector of various geometry represented by space height ratio(e/h). Next, ambient air was then directed over the tube bundle at varying Reynolds number and the effect of baffle spacing (PR), Space height ratio (e/h) and inclination angle(a) of deflectors on performance of heat exchanger was experimentally analyzed. Findings The heat transfer augmentation of heat exchanger for given operating condition is strongly dependent on geometry, inclination angle of deflector and baffle spacing. Originality/value An average improvement of 1.42 times in thermal enhancement factor was observed with inclination angle of 30°, space height ratio of 0.4 and a pitch ratio of 1.2 when compared to a heat exchanger without a baffle plate under similar operating conditions.

Optimizing heat transfer in solar air heater ducts through staggered arrangement of discrete V‐ribs

AbstractThis research paper details an experimental study on airflow dynamics in a solar air heater. The heater's design incorporates unique, discrete V‐shaped ribs with staggered elements to enhance thermal performance. The study investigates the influence of various roughness parameters on flow characteristics. These parameters include a relative coarseness pitch (P/e) ratio of 12, a rib inclination angle (α) of 60°, a relative coarseness height (e/Dh) of 0.043, and a staggered element arrangement with a positioning ratio (p′/P) of 0.65. Additionally, the investigation includes scenarios with three gaps (Ng) between elements and a gap‐to‐rib width (g/e) ratio of 4. The research focuses on how changes to the Reynolds number, ranging from 3000 to 14,000, and alterations to the ratio of staggered element positioning to rib height (r/e), from 2 to 5, impact the flow dynamics. The outcomes indicate a significant boost in heat transfer performance, with the Nusselt number rising to 3.76 compared with a conventional smooth duct. The highest thermal efficiency recorded was 86%, at an r/e ratio of 3.5. These results underscore the potential of using discrete V‐ribs with staggered elements in rectangular ducts to improve heat transfer efficiency.

Influence of nozzle profile on submerged pipe jet impingement heat transfer

ABSTRACT Current work focuses on enhancing the performance of solar air heater by employing vertical submerged pipe jets featuring different profiles: circular, square, triangular, and rectangular. The study investigates parameters including jet diameter ratio d / D h ranging from 0.044 to 0.11 and the jet spacing ratio ( Sj / D h ) varying from 0.108 at 0.433 while keeping the streamwise ( X / D h ) and spanwise Y / D h pitch ratio fixed at 0.867. The Reynolds number Re ranges from 3,000 to 18,000. Initial results for all the profiles were obtained through CFD simulations, indicating that the circular pipe jet demonstrates superior heat transfer and thermo-hydraulic performance parameter (THPP). The experimental validation of circular profile pipe jet showed a maximum THPP of 2.69 achieved at a d / D h of 0.066 and Sj / D h of 0.217, with a Reynolds number of 15,000.

Design of Archimedes screw turbine: exploring the influence of pitch ratio, radius ratio, and inclination angle on outer diameter size

Design of Archimedes screw turbine: exploring the influence of pitch ratio, radius ratio, and inclination angle on outer diameter size