Addition Of Ribs Research Articles

Enhanced Impeller Gas-Liquid Flow Using Ribs for High Performance of Centrifugal Pump

Transporting two-phase fluids presents a challenge due to their negative effects on centrifugal pump performance. The accumulation of gas bubbles in the pump impeller forms large gas pockets, reducing efficiency. This work aims to improve the performance of a two-phase flow centrifugal pump by modifying the pump impeller through the addition of ribs. These ribs are positioned near gas bubble accumulation. The modified impeller helps to disperse this accumulation, thereby enhancing pump performance. A study was conducted to evaluate the effect of ribs on the pump efficiency. The results showed a negative effect in low (GVF) and single-phase flows. However, at high GVF, the ribs significantly improved head up to 9%. Moreover, rib characteristics, such as diameter and radial position, were key parameters affecting the pump's efficiency. The ribs with a diameter of 1 mm and a radial position of 33 mm showed the best performance.

Effect of Honeycomb Geometrical Parameters on Equivalent Radiated Power and Frequency Response of Motor Casing and Gearbox Surface of a Powertrain

ABSTRACTThe powertrain, as a central source of noise and vibration, is crucial in determining the overall NVH (noise, vibration and harshness) performance of vehicles, necessitating the optimisation of its structural components for improved durability and passenger comfort. This paper investigates the influence of key geometrical parameters—cell thickness, skin thickness and cell length—on the complex frequency modes of honeycomb and square sandwich structures using the Altair OptiStruct solver 2022 and fast Fourier transform analyser. The driven and non‐driven ends of a motor casing and a gearbox, represented by honeycomb structures and ribs, were subjected to an evaluation of equivalent radiated power (ERP). The results show that the square structure performs better at higher skin thickness when resisting severe lateral stresses than the honeycomb while being less stiff at higher cell thickness. Notably, smaller cell length had a substantial impact on the modes of the honeycomb structure, whereas larger cell length had an impact on the square structure. Response surface methodology was used to optimise the modal frequencies of both square and honeycomb panels simultaneously. An ideal cell length of 5.88 mm, skin thickness of 1.303 mm and cell thickness of 0.381 mm were found for the honeycomb construction, yielding a composite desirability of 0.981. On the other hand, with a cell length of 5.045 mm, skin thickness of 1.484 mm and cell thickness of 0.331 mm, the square structure achieved a composite desirability of 0.989. It is interesting to note that the driven end casing of the motor casing made more noise with the addition of ribs than the non‐driven end and gearbox. But compared to the original powertrain model, adding a honeycomb structure resulted in a noise reduction of about 10%.

Numerical simulation and optimization analysis of low temperature adsorption hydrogen storage

In this paper, a two-dimensional axisymmetric hydrogen storage tank model is established based on the D-A model using software to simulate the activated carbon adsorption hydrogen storage filling process numerically. The distribution of pressure inside the tank under the boundary conditions of 0.5 atm–1 atm is obtained, and the trends and rates of pressure changes inside the tank under different boundary conditions are compared. The temperature distribution inside the tank is investigated under the initial temperature of 293.15 K, the external condition of 77 K, and the convective heat transfer coefficient inside and outside the tank is 20 W/(m2·K), and the influence of adsorption materials on the temperature distribution inside the tank is compared with that of different thermal conductivity coefficients, and the general trend is that the temperature is higher and then lower, the temperature inside the tank is relatively high near the center axis, and the temperature near the tank wall is relatively low, and the addition of ribs can The addition of ribs can reduce the temperature inside the tank. This paper also calculates the adsorption amount of hydrogen at different pressures (0–7 MPa) and temperatures (80 K–260 K), and finds that the adsorption amount is the largest at 80 K and 7 MPa, with a value of 39.3 mol/kg. The novelty of this study is the coupling of many different physical fields to bring the results closer to reality and to give directions for optimization.

Characteristics of photothermal transfer and biochemical reaction in up-flow direct absorption hydrogen reactor with embedded ribs

The anaerobic fermentation process of microbial community is a promising method to treat wastewater with high ammonia nitrogen, but it needs to provide suitable temperature. An innovative direct absorption anaerobic reactor was established to reduce the temperature fluctuation of biogas slurry by adding ribs to ensure the high efficiency and stability of anaerobic fermentation process. The effects of flow rate and number of ribs on gas production in the process of photothermal conversion and anaerobic fermentation were analyzed by numerical simulation. The results show that the addition of ribs can effectively reduce temperature fluctuation and increase gas production. Compared with 2269.7 mL/L gas production and temperature fluctuation of up to 8 K without ribs, the gas production increased by 863.1 mL/L and decreased to 0.1624 K when the number of ribs was 9, respectively. Simultaneously, a curve was fitted according to gas production to predict the best working conditions.

Numerical Computation on Natural Convection Heat Transfer From an Isothermal Sphere With Semicircular Ribs

Abstract For the very first time, this study attempts to address the heat dissipation from an isothermal ribbed sphere under the action of pure natural convection. Semicircular ribs of different radii are superimposed azimuthally on the outer surface of a sphere. The addition of ribs on the sphere serves a dual purpose in its practical applications: beautification of electronic devices such as spherical light sources as well as an increase in heat dissipation from the hot surface, which prevents the electronic component from getting overheated. Finite volume method-based axisymmetric numerical simulations are performed in the laminar flow regime for the following ranges of nondimensional parameters: Rayleigh number (102 ≤ Ra ≤ 108), inter-rib-spacing to sphere diameter (0.191 ≤ P/D ≤ 0.785), and rib-radius to sphere diameter (0.03 ≤ R/D ≤ 0.083). The main target of this study is to identify the critical parameters for heat transfer enhancement from the ribbed sphere compared to a conventional plane sphere. The results obtained from this work show that the average Nusselt number increases with an increase in Ra and P/D, whereas it decreases as R/D increases. Effectiveness of the ribs (εrib) and critical Rayleigh numbers (Racr), corresponding to εrib = 1, are also calculated. Ribs are more effective in heat dissipation at low Ra and P/D and high R/D. A correlation for the average Nusselt number is also developed in this work, which would help design a better thermal management system.

Warpage investigation of carbon/PEEK discontinuous long fibre thin panels

Discontinuous Long Fibre (DLF) composites, composed of randomly-oriented strands of chopped unidirectional pre-impregnated tape, have been used in the aerospace industry to produce intricate, net-shape parts with complex features – replacing complicated metallic brackets with single, lightweight parts. Carbon/PEEK DLF composites suffer from warpage problems driven by several factors including their high processing temperatures and semi-crystalline matrix shrinkage. This work aims to characterize warpage of thin-gauge parts and pursue mitigation. Results showed that the magnitude of warpage reduces with decreasing strand size and increasing thickness. At thicknesses greater than 2 mm, warpage appeared relatively stable. The introduction of ribbed features was explored as a mean of mitigating warpage by increasing part stiffness. No significant impact on the magnitude of warpage was observed within parts. However, the addition of ribs helped to control the warped shape of the part.

Thermal and entropy analysis of a manifold microchannel heat sink operating on CuO–water nanofluid

An increase in area and disturbance of flow by introducing ribs in a microchannel system has proven to be effective in thermal management. On the other hand, nanofluid as a new coolant could also provide a much-needed performance boost. The performance of a manifold microchannel heat sink utilising nanofluid as the coolant and ribs for flow mixing has been investigated. The study is conducted with CuO–water nanofluid, Reynolds number of 100–400 and CuO nanoparticle volume fraction up to 4%. The results show that CuO–water nanofluid produced a higher thermal performance at higher concentration and Reynolds number with a corresponding increment in pressure drop. When compared to water, the Nusselt number increased from 4.4 to 23.67% at Reynolds number of 100 and CuO concentration of 4%. The addition of ribs on the sidewall of the manifold microchannel only showed a slight enhancement of up to 6.8% in the Nusselt number. Similarly, the thermal enhancement factor ranging from 1.03 to 1.07 is observed for the ribbed manifold microchannels, indicating better overall performance when compared to the microchannel without ribs.

Optimization of Plastic Moulding by Reducing Warpage With the Application of Taguchi Optimization Technique & Addition of Ribs in Washing Machine Wash Lid Component

This paper deals with the optimization of plastic moulding by reducing warpage with the application of Taguchi optimization technique & part design modifications. Taguchi optimization technique is used for determining the optimum plastic injection moulding process parameters. In part design modifications, ribs are added to the wash lid component to provide additional strength to the washing machine. Analysis of the process parameters are initially carried out by utilizing the combination of process parameters based on three-level of L27 Taguchi orthogonal design. Further, signal-to-noise (S/N) ratio is applied to find the optimum process parameters for warpage defect in the wash lid component. The design modifications and analysis for warpage using optimum parameters obtained from S/N ratio using Pro-E design software and Solid Edge Plastic analysis software. The results obtained reveals that improvement in total warpage is 22.0% & in X-direction it is 37% and stress distribution is by 28% which proves that the strength of the wash lid has increased.

06/01351 Augmentation of heat transfer coefficient by using 90† broken transverse ribs on absorber plate of solar air heater: Sahu, M. M. and Bhagoria, J. L. Renewable Energy, 2005, 30, (13), 2057–2073

Three-dimensional laminar forced convective flow and entropy generation in a 180-deg curved rectangular duct with longitudinal ribs equipped on the heated wall are investigated by numerical methods. The development of secondary vortices, temperature and local entropy generation distributions as well as the overall entropy generation in whole flow fields, including the entrance and fully developed region, are analyzed. The effects of rib size are particularly highlighted in the present paper. Calculations of cases with various rib sizes under different Dean numbers and external heat fluxes are carried out to examine the influence of rib on the flow field and entropy generation. The entropy generated from frictional irreversibility and heat transfer irreversibility is investigated separately in detail. The results reveal that the addition of rib can effectively reduce the entropy generation from heat transfer irreversibility since the secondary vortices are augmented by the rib, through which the heat transfer performance is enhanced, in turn making the temperature gradient become smoother. Nevertheless, the entropy generation due to frictional irreversibility is raised at the same time because larger fluid friction is resulted from the wider solid walls and the complex flows disturbed by ribs. Due to the opposite influences of rib on the entropy generations from irreversibilities, the analysis of the optimal trade-off is carried out based on the minimal entropy generation principle. The optimal rib size which induces the minimal entropy generation in the flow fields is found to be dependent on the external heat flux and Dean number. Even under some flow conditions, the resultant entropy generation could not be reduced but becomes worse when ribs are added. These results provide worthwhile information for considerations of adding ribs on a curved duct and the determinations of rib sizes from view point of thermodynamic second law.

Ultimate Bearing Capacity of Ribbed Strip Footing Under Vertical and Inclined Loads

This paper investigates the ultimate bearing capacity of a strip footing stiffened with ribs connected to its lower surface.The effect of number and depth of ribs on the bearing capacity are investigated numerically using the finite element method. Different footings resting on a clayey soil are analyzed under vertical and inclined loadings. A new efficiency factors (ER) is proposed to be added to the general bearing capacity equation in order to take the effect of ribs into consideration. The results indicate that, tire ultimate bearing capacity of a strip footing is improved via the addition of ribs.

Numerical investigation on laminar forced convection and entropy generation in a curved rectangular duct with longitudinal ribs mounted on heated wall

Three-dimensional laminar forced convective flow and entropy generation in a 180-deg curved rectangular duct with longitudinal ribs equipped on the heated wall are investigated by numerical methods. The development of secondary vortices, temperature and local entropy generation distributions as well as the overall entropy generation in whole flow fields, including the entrance and fully developed region, are analyzed. The effects of rib size are particularly highlighted in the present paper. Calculations of cases with various rib sizes under different Dean numbers and external heat fluxes are carried out to examine the influence of rib on the flow field and entropy generation. The entropy generated from frictional irreversibility and heat transfer irreversibility is investigated separately in detail. The results reveal that the addition of rib can effectively reduce the entropy generation from heat transfer irreversibility since the secondary vortices are augmented by the rib, through which the heat transfer performance is enhanced, in turn making the temperature gradient become smoother. Nevertheless, the entropy generation due to frictional irreversibility is raised at the same time because larger fluid friction is resulted from the wider solid walls and the complex flows disturbed by ribs. Due to the opposite influences of rib on the entropy generations from irreversibilities, the analysis of the optimal trade-off is carried out based on the minimal entropy generation principle. The optimal rib size which induces the minimal entropy generation in the flow fields is found to be dependent on the external heat flux and Dean number. Even under some flow conditions, the resultant entropy generation could not be reduced but becomes worse when ribs are added. These results provide worthwhile information for considerations of adding ribs on a curved duct and the determinations of rib sizes from view point of thermodynamic second law.

Automated rib location and optimization for plate structures

For a given loading, the stiffness of a plate or shell structure can be increased significantly by the addition of ribs or stiffeners. Hitherto, the optimization techniques are mainly on the sizing of the ribs. The more important issue of identifying the optimum location of the ribs has received little attention. In this investigation, a methodology has been developed for the automatic determination of the optimum locations of the ribs for a given set of design constraints.

THERMOELASTIC PURE BENDING OF NONHOMOGENEOUS PRISMATIC BARS

By using a Bernoulli-Euler type beam theory, a simple solution is obtained for the general problem of the thermoelastic pure bending of nonhomogeneous prismatic bars. Within this framework, the elastic modulus and temperature distributions can vary arbitrarily over the bar cross-section, and the elastic modulus and thermal expansion coefficients can be temperature dependent. The analysis is valid for time-dependent temperature variations and can therefore be used for analyzing warping and residual stresses induced by transient temperature fields. An analysis of a bi-material channel-sectioned beam is used to show that the addition of ribs significantly reduces the thermoelastically induced warping in bimaterial strips caused by temperature excursions. It is shown that thermoelastic warping in a three-layer tri-material strip cannot be reduced by using a middle layer with an elastic modulus much lower than the modulus of the surrounding layers.

Flow Regimes in Two-Dimensional Ribbed Diffusers

Water table flow visualization tests of a straight wall diffuser and corresponding ribbed diffuser were conducted over a wide range of total divergence angles and diffuser length to throat width ratios. Rib parameters such as inter-rib cavity depth to width ratio, inter-rib cavity width, rib thickness, and number of ribs were varied, as well as rib contour. Motion pictures were obtained of the secondary flow patterns occurring within the inter-rib cavities, and hot film measurements were made to determine the extent of velocity fluctuations induced by the cavities. In general, the addition of ribs increased the no-appreciable stall regime.