Development Of New Correlation Research Articles

Development of new correlation for the prediction of power number for closed clearance impellers using machine learning methods trained on literature data

AbstractThe accurate estimation of the power number for closed clearance impellers holds significant importance in industries such as chemical, biochemical, paper and pulp, as well as paints, pigments, and polymers. Existing state‐of‐the‐art correlations for predicting power numbers, however, are inaccurate for impeller Reynolds number . In this study, we compiled a dataset of 1470 data points from 15 research articles in the open literature, covering five types of impellers: (i) anchor; (ii) gate; (iii) single helical ribbon; (iv) double helical ribbon; and (v) helical ribbon with screw. Six machine learning models, namely artificial neural networks (ANN), CatBoost regressor, extra tree regressor, support vector regressor, random forest, and XGBoost regressor, were developed and compared. The results revealed that ANN emerged as the most efficient model, demonstrating the highest testing R2 value of 0.99 and the lowest testing MAPE of 7.3%. Further, we used the ANN model to develop a novel set of process correlations to estimate impeller power numbers for the industrially important anchor and double helical ribbon impellers: which significantly outperform the existing state‐of‐the‐art correlations available in literature.

Investigation of convective heat transfer in a cold flow pebble bed nuclear reactor using advanced pebble probe heat transfer sensor

The aim of this study was to investigate the local heat transfer coefficients between the pebbles and the coolant gas in a PBR using an advanced measurement technique that consists of a heated pebble probe, a micro-foil heat flux sensor mounted flush on the surface of the heated pebble probe, and a thermocouple in the center of the bed void in front the sensor. In this work, the local heat transfer coefficients were derived at various axial levels, radial and angular locations and at different superficial inlet gas velocities that cover both transitional and turbulent flow conditions. The local heat transfer coefficients were found to be 22-32%, 34-39%, and 18-20% higher near the wall at superficial inlet gas velocities of 0.3,1.2, and 2m/s, respectively. This is due to higher volumetric flow at the wall where larger void in the pebble bed exists compared to the center region of the bed where the flow of the gas in the packed bed follows the least resistance path. Large deviations were obtained between the experimental overall heat transfer coefficients in the bed and the predictions of seven correlations that were selected from the literature. Furthermore, these correlations cannot predict the local heat transfer coefficients inside the PBR. This necessitates the development of new correlations for the prediction of the local heat transfer coefficients using the data obtained in this work. A pseudo-3D correlation was developed and was found to provide predictions that are in good agreement with the experimental values for the conditions used, with an averaged absolute relative error (AARE) of 3.33% at high Reynolds numbers for our operating and design conditions.

A comparative experimental investigation of dynamic viscosity of ZrO2/DW and SiC/DW nanofluids: Characterization, rheological behavior, and development of new correlation

In general, A nanofluid is a substance in which solids and fluids are mixed. The nano-powder of zirconium oxide (ZrO2) and silicon carbide (SiC) was dispersed into the distilled water (DW) using the widely adopted two-step technique. A Brookfield viscometer was used to measure the viscosity of the nanoparticles of ZrO2/DW and SiC/DW, where the temperature ranged between 20 and 60 °C and different solid volume fractions of 0.025, 0.05, 0.075, and 0.1 % were used. An examination of the mono nanofluids of ZrO2/DW and SiC/DW was conducted to assess their rheological behaviour. The findings of the experiments revealed that the Newtonian behaviour did not change when the nano-powder was added. Increasing the solid volume fraction of the nanoparticles and lowering the temperature resulted in the sample's dynamic viscosity being augmented. Hence, as the temperature rose, nanoparticles had a more observable impact on the viscosity. Furthermore, the findings showed that the increase in the ZrO2/DW nanofluid's viscosity peaked at 226.3 %, whereas for the SiC/DW nanofluid, it was 110.5 %. Additionally, according to the results of the experiments, new correlations capable of predicting the investigated nanofluids' viscosity in relation to solid concentration and temperature has been suggested. The study's results could motivate expanded utilization of nanofluids by researchers working on energy applications.

Development of New Correlation Fines Content, NSPT and CPT Using Neural Network Approach and Multilinear Regression to Support Liquefaction Hazard Analysis

Identification and characterization of constituent soil types in the form of Fines Content (FC) values are essential in analyzing the potential of soils to be liquefaction. Multiple Linear Regression is one of the fundamental statistical models used to determine the causality between target and predictor geotechnical parameters. The study used multilinear regression approaches and artificial neural networks to get optimal results from FC predictions. The study considers the correlation between the SBT Index and FC and several other parameters such as NSPT, Depth, Totally Overburden Stress, Initially Overburden Stress, and Sleeve Friction. The coefficient of determination resulting from the regression process shows a reasonably strong relationship between the independent and target parameters, as much as 61.4%. In comparison, the Neural Network is 96.928%, which indi-cates a nonlinear influence.

Characterization of a Non-Darcy Flow and Development of New Correlation of NON-Darcy Coefficient

Darcy’s law has long been used to describe the flow in porous media. Despite the progress that took place in oil production industry research, it became clear that there is a loss of pressure, especially in the area near the wellbore region, where Darcy’s law is not applicable. For this reason, Forchheimer presented his equation in 1910, where he added a new term to Darcy’s law dealing with pressure loss due to inertial forces by introducing a new term, the β coefficient, into the equation. This paper presents a study of fluid flow through porous media, where water was used as a working fluid. Furthermore, the characteristics of the non-Darcy flow were analyzed by presenting the corresponding pressure and velocity gradient curves for each pressure. Extensive analysis indicates that many of the correlations available in the literature either have defective units or are the product of a small number of experiments. In this study, we benefit from relatively large samples, the radial flow, and the perforation in the middle of the samples. The properties of the samples were measured using mercury intrusion porosimetry. It was found that there is a direct relationship between the porosity and the grain’s size; the greater the size of the grains, the greater the porosity, and vice versa. The non-Darcy coefficient term, β, is found to be inversely proportional to the porosity and permeability. In a previous study, the β was investigated for compressible flow scenarios; however, this study calculated it for an incompressible flow. Finally, by analyzing the β values of both studies, we could deduce new novelty correlations for the β coefficient term, where the permeability, porosity, and tortuosity are included.

Effects of Concentration and Temperature on the Viscosity and Thermal Conductivity of Graphene–Fe3O4/Water Hybrid Nanofluid and Development of New Correlation

Effects of Concentration and Temperature on the Viscosity and Thermal Conductivity of Graphene–Fe3O4/Water Hybrid Nanofluid and Development of New Correlation

Experiments in free falling and downward cocurrent annular flows – Characterization of liquid films and interfacial waves

Falling liquid films and downward cocurrent flows in rounded shape pipes have been experimentally studied during the last decades, estimating the evolution of its major characteristics. The most important variables during the formation and growth of surface waves in falling downward flows have been measured using conductance probes.The main objective of the current research paper is to study the dependency of the characteristics of the thin liquid layer for downward cocurrent annular flows. The GEPELON experimental facility consists of a vertical pipe with 3.8 m of useful test length. Two pipe diameters have been analysed in this experimental study, 42 and 30 mm, in which the range covered by the liquid Reynolds number varies between 570 and 8500 and 800–7900 respectively, while the gas Reynolds numbers vary from 0 to 7.9·104 and from 0 to 1.1·105 respectively for the mentioned pipe diameters. Up to five conductance probes have been placed along the pipes test sections to capture the liquid film thickness fluctuations along time at different distances of the pipe entrance for both developing and fully developed regions.After the study and analysis of the experimental data, the central point of this paper has been the development of new correlations for the liquid film thicknesses and the two major properties of the interfacial waves. Their adjustment procedure has been carried out in terms of dimensionless numbers, aiming to provide more general relationships. In particular, the magnitudes that characterise the interface behavior have been measured, particularly film thicknesses, average disturbance wave amplitudes, and disturbance wave frequencies for each boundary condition.An additional part of the document contains an extensive comparison between the results obtained in this study and the data and expressions of other authors. It has been confirmed the significant dispersion existing among different researchers, especially when analysing variables related to the interfacial waves. This highlights the lack of knowledge in some aspects even today. The different correlations proposed have been calculated based on the best fit of the data from all the series of experiments carried out in this study. Comparisons of the behaviour of these correlations with data from other researchers have also been included.

Development of New Correlations and Parametric Optimization in Nanofluid Flow through Protruded Roughened Square Channel

This study discusses the optimization of heat-transfer parameters in nanofluid flow through a rough square surface channel including a protruded rib compound transverse pattern using response surface methodology (RSM). Flow and geometrical characteristics are optimized, resulting in optimal flow friction and heat transfer performances. The comparison of RSM’s estimated values to experimentally observed values was abandoned. The results demonstrate that the RSM-calculated values agree with the observed values and are within the 5.5 percent uncertainty limitations. Statistical correlations for Nusselt number and friction factor have been developed as functions of protrusion transverse rib height, protrusion transverse rib diameter, X-axis pitch, Y-axis pitch, and Reynolds number. These correlations have been found to predict the values within the error limits of ±8.9% and ±8.7%, respectively. On the basis of correlations developed for Nusselt number and friction factor, an attempt has been made to compare the thermohydraulic performance of protruded roughened square channel.

Sensitivity analysis of design parameters and power gain correlations of bi-facial solar PV system using response surface methodology

Sensitivity analysis of design parameters and power gain correlations of bi-facial solar PV system is presented in this paper. The main objectives are to study the effects of albedo, tilt angle and height from the ground on the performance of the system; determine the optimum operating conditions; and the development of new correlations for the annual energy yield and bifacial gain of bPV solar system. Three primarily significant installation parameters, albedo [10%, 50%, 90%], tilt angle [15°, 25°, 35°] and height [0.5 m, 1 m, 1.5 m] are investigated with PVSYST for bifacial and mono-facial PV modules. The response surface methodology (RSM) based optimization method is used to determine the optimum conditions and the interaction of these three parameters on the performance of bPV solar system. New quadratic equations or correlations are introduced to estimate the annual energy yield and bifacial gain of bPV. The results show that the albedo is the most significant parameter between tilt angle and height. The increase in albedo factor and height of bPV modules from ground increase the energy yield. In this study, the optimum tilt angle of bPV is found to be 35°for higher albedo and elevation of bPV from the ground as compared to 25° of mPV. An average daily bifacial gain of 35.68% can be achieved in clear sunny day with 90% albedo, tilt angle of 35° and at height of 1.5 m. The maximum specific productions of 192.4 kWh/kWp and 160.6 kWh/kWp are observed in May for bPV and mPV, respectively while the maximum bifacial gain of 21.93% is found in July.

Effect of base fluids on thermo‐physical properties of SiO2 nanofluids and development of new correlations

The enhanced thermal properties are the prominent objective behind the usage of nanofluids. Hence, it is necessary to study the base/nanofluid physical properties at various conditions. This article projects the experimental results of thermal conductivity and viscosity of two different nanofluids. The ratio was considered as 60:40 and 40:40 by volume in water and ethylene glycol, respectively. The preparation of nanofluids was started by scattering SiO2 nanoparticles in EG and “water” (W) blended in “60:40” (60EGW) and “40:60” (40EGW) ratio by volume. The regression analysis was conducted with available data, and correlations were formulated for thermal properties. The nanofluids were used in evaluating “viscosity” and “thermal conductivity” experimentally. From the results, the SiO2 particles have achieved an enhancement of 34% and 32% in thermal conductivity with the two base fluids. Similarly, an enhancement of 102% and 62% was reported in viscosity. Hence, it can be observed that SiO2 nanofluids in 40EGW nanofluid are better heat transfer fluids when compared with SiO2 in 60EGW nanofluid.

Heat transfer analysis using zinc Ferrite/water (Hybrid) nanofluids in a circular tube: An experimental investigation and development of new correlations for thermophysical and heat transfer properties

For heat transfer analysis, the thermal properties of the heat transfer fluid is aninterestingtopic of current research. The hybrid nanofluids have better effective thermal conductivity, which is being used to improve the heat transfer rate. This experimental study presents the heat transfer characteristic of aqueous Zinc Ferrite/water (ZnFe2O4/water) nanofluids. ZnFe2O4/waternanofluids were prepared, suspending hybrid nanoparticles in the basefluids with 0.01 wt% CTAB as surfactant with different weight concentrations i.e., (0.02, 0.05, 0.1, 0.2, 0.5 wt%). Detailed surface properties of ZnFe2O4/waternanofluids were characterized using EDS, TEM, and UV–vis spectroscopy. Experiments were conducted to find out the viscosity, thermal conductivity,and convective heat transfer coefficient of ZnFe2O4/waternanofluids using laminar flow in a tube geometry using constant heat flux (CHF) boundary condition. Results revealed 11.8% improvement in the thermal conductivity for ZnFe2O4/waternanofluids, whereas an enhancement of 42.99% was observed in the convective heat transfer coefficient using 0.5 wt% of the nanofluids.The thermal conductivity results indicate that ZnFe2O4/waternanofluids have higher thermal conductivity for all the studied nanofluids. From the experimental data, new correlations for finding the thermophysical properties and Nusselt number has been proposed. The novel correlation established will help scientists and engineers for further insight into future research.

Development of new correlations for heat transfer and pressure loss due to internal conical ring obstacles in an impinging jet solar air heater passage

This paper experimentally studies the solar air heater rectangular passages with different types of inside conical ring obstacles for heat transfer enhancement. The experiments were conducted in a turbulent flow regime with Reynolds number ranging from 5,000 to 23,000 under uniform wall heat flux. The optimum values of parameters for obstacle roughened surface arrangement have been obtained and discussed. The optimum value of heat transfer is observed at relative inside conical ring height (HR/DH) of 0.110, ratio of inlet flow diameter to inner print diameter of ring (DIR/DBR) of 1.7, ratio of ring diameter to ring height (DO/HR) of 2.33, relative X-axis pitch (XS/DO) of 5.28 and relative Y-axis pitch (YS/DO) of 3.42. The statistical correlations of Nusselt number and friction factor are also developed from the experimental results of inside conical ring obstacles in round jets impingement solar air rectangular passage.

Development of new correlations for heat transfer and friction loss of solid ring with combined square wing twisted tape inserts heat exchanger tube

ABSTRACT An experimental analysis has been carried out for heat transfer and turbulent flow in a heat exchanger circular tube with solid ring with combined square wing twisted tape (TT) inserts. Experimentations are performed varying the solid ring with combined square wing TT insert parameters, such as changing the number of TT inserts from 1.0 to 4.0, ring pitch ratio from 0.5 to 2.0, wing pitch ratio from 2.0 to 3.5, wing depth ratio from 0.083 to 0.333, ring diameter ratio from 0.831 to 0.932, and Reynolds number in the range of 3,000–21,000. The experimental results show that the heat transfer is increased around 5.66 times more than the plane circular tube. The thermal hydrodynamic performance is evaluated for the optimum range of solid ring with combined square wing TT insert parameters. Statistical correlations are developed and a deviation of correlation data from the experimental data of Nusselt number and friction factor is about ± 9% and ± 6%, respectively. The correlation is helpful in prediction of the thermal performance for turbulent flow through a circular tube with solid ring with combined square wing twisted tape inserts.

Measurement of pH of the Three Nano Fluid and Development of New Correlations

Measurement of pH of the Three Nano Fluid and Development of New Correlations

Flow boiling heat transfer in mini channel with serrated fins: Experimental investigation and development of new correlation

Extensive studies have been conducted on flow boiling heat transfer in mini or micro channels with square and circular configurations. Few investigations, however, have focused on a channel configuration featuring serrated fins. Therefore, the present study experimentally investigated the flow boiling heat transfer characteristics of refrigerant R134a in two mini channels with serrated fins. The equivalent diameters are 1.28 mm with 11 channels and 1.59 mm with 9 channels. Quantitative experiments were conducted under a mass flux of 60–308 kg/(m2.s), heat flux of 6–48 kW/m2, saturation pressure of 0.27–0.45 MPa and vapour quality of 0–1. Flow patterns during flow boiling in the channel were also captured and analysed. Results indicated that in the low vapour quality region, the local heat transfer coefficient increases with both heat flux and saturation pressure. However, the influence of mass flux is related to heat flux. The flow pattern in this region starts with dispersed bubbly flow and develops to vigorous bubbly flow. Slug flow and annular flow are then observed along the flow direction of the refrigerant. In contrast, in the high vapour quality region, the influence of heat flux and saturation pressure seem to vanish and higher refrigerant mass flux corresponds to a greater heat transfer coefficient. The annular flow continues in this region with intermittent dry-out, which leads to a sharp decrease in the heat transfer coefficient. As the existing empirical correlation for calculating flow boiling heat transfer coefficient fails to give a reasonable prediction for the present experimental data, a new correlation was proposed with a mean absolute relation deviation of 15.0% for all 1429 data points. The present experimental data and new proposed correlation can provide meaningful guidance for the design of a mini channel two phase heat exchanger with serrated fins.

Flow condensation in a mini channel with serrated fins with jet impingement cooling: Experimental study and development of new correlation

The present study experimentally investigated the heat transfer characteristics of flow condensation in a mini channel with serrated fins. The hydraulic diameter of the aluminum channel was 1.28 mm with 11 offset rectangular channels. The vapor of refrigerant R134a was cooled by cold water with jet impingement. After the calibration of jet impingement cooling, the influences of different parameters on condensation heat transfer were identified with the experimental conditions of vapor quality from 0 to 1, heat flux from 5 kW/m2 to 52 kW/m2, mass flux from 72 kg/(m2·s) to 145 kg/(m2·s) and saturation pressure from 0.38 MPa to 0.50 MPa. Flow patterns during condensation were also observed through the visualization design of test section. The experimental results reveal that the vapor quality and mass flux have insignificant influence on the local heat transfer coefficient. The heat transfer coefficient increases with the heat flux and decreases with the saturation pressure. Annular flow is dominant during the whole condensation process. As the existing empirical correlations fail to give reasonable prediction of the present experimental results, a new one is developed with the mean relative deviation and mean absolute relative deviation of 2.3% and 12.0%, respectively. The present work can provide valuable guidance for the design of mini channel condenser for engineering application.

Experimental investigation and development of new correlation for flow boiling heat transfer in mini-channel

The flow boiling heat transfer of refrigerant R134a in horizontal multiport mini-channel was experimentally investigated in this paper. Two kinds of mini-channels made of aluminum alloy with the hydraulic diameter of 0.63 mm for 23 rectangular channels and 0.72 mm for 14 rectangular channels were studied. Electric heating film was adopted to provide direct uniform heat flux. The experimental results were obtained with the vapor quality between 0 and 1, the heat flux ranging from 10 to 60 kW/m2, the mass flux ranging from 128 to 560 kg/(m2.s) and the saturation pressure from 0.22 to 0.58 MPa. It was found that nucleate boiling dominates in the low vapor quality region and the heat transfer coefficients of mini-channel are higher than those in conventional channel. The heat transfer coefficients increase with the increasing of both heat flux and saturation pressure but have little dependence with the mass flux. In the high vapor quality region, connective boiling is the main contributor. Heat flux and saturation pressure have little influence on the heat transfer coefficients, but the influence of mass flux is obvious. There is a small increase in heat transfer coefficient with an increase of mass flux. Accordingly, a new correlation for flow boiling heat transfer in mini-channel of R134a was proposed based on Gungor and Winterton correlation. The mean relation deviation is −1.76% and the mean absolute relation deviation is 19.0% respectively. This new correlation is proved to have an obvious accuracy improvement in predicting the flow boiling heat transfer coefficient of R134a in mini-channel. The present work can provide a guidance to the design of mini-channel heat exchanger.

Development of new correlations for the oil formation volume factor in oil reservoirs using artificial intelligent white box technique

Oil formation volume factor (OFVF) is considered one of the main parameters required to characterize the crude oil. OFVF is needed in reservoir simulation and prediction of the oil reservoir performance. Existing correlations apply for specific oils and cannot be extended to other oil types. In addition, big errors were obtained when we applied existing correlations to predict the OFVF. There is a massive need to have a global OFVF correlation that can be used for different oils with less error. The objective of this paper is to develop a new empirical correlation for oil formation volume factor (OFVF) prediction using artificial intelligent techniques (AI) such as; artificial neural network (ANN), adaptive neuro-fuzzy inference system (ANFIS), and support vector machine (SVM). For the first time we changed the ANN model to a white box by extracting the weights and the biases from AI models and form a new empirical equation for OFVF prediction. In this paper we present a new empirical correlation extracted from ANN based on 760 experimental data points for different oils with different compositions. The results obtained showed that the ANN model yielded the highest correlation coefficient (0.997) and lowest average absolute error (less than 1%) for OFVF prediction as a function of the specific gravity of gas, the dissolved gas to oil ratio, the oil specific gravity, and the temperature of the reservoir compared with ANFIS and SVM. The developed empirical equation from the ANN model outperformed the previous empirical correlations and AI models for OFVF prediction. It can be used to predict the OFVF with a high accuracy.

An experimental study and development of new correlation for condensation heat transfer coefficient of refrigerant inside a multiport minichannel with and without fins

This paper is dedicated to the experimental study and development of new correlation for condensation heat transfer in horizontal rectangular multiport minichannel with and without fins using R134a. A new experimental apparatus has been fabricated in order to obtain explicit local condensation heat transfer coefficient measurements over a range of test conditions. The test section is an 852mm long horizontal rectangular multiport minichannel with and without fins having 20 channels with a hydraulic diameter of 0.64mm and 0.81mm. The measurements were done over a range of saturation temperature from 30 to 35°C with mass fluxes ranging from 50 to 200kg/m2s. The effects of vapor quality, mass fluxes, channel geometry, and saturation temperature on the heat transfer coefficient have been clarified and analyzed. The experimental results were compared with the well-known condensation heat transfer models available in the open literature. All of the existing correlations were failed to capture the present experimental heat transfer coefficient with a high degree of accuracy. Asa consequence, a new condensation heat transfer correlation was developed based on the present experimental data and validated with 750 data points collected from the available journal.

Experimental investigation and development of new correlation for influences of temperature and concentration on dynamic viscosity of MWCNT-SiO 2 (20-80)/20W50 hybrid nano-lubricant

Abstract In current research, MWCNT-SiO2/oil hybrid nano-lubricant viscosity is experimentally examined. By dispersing 0.05%, 0.1%, 0.2%, 0.4%, 0.8% and 1% volume of MWCNTs and SiO2 nanoparticle into the engine oil SAE 20W50, the temperature and solid volume fraction consequences were studied. At 40 to 100 °C temperature, the viscosities were assessed. The results indicated Newtonian behavior for the hybrid nano-lubricant. Moreover, solid volume fraction augmentation and temperature enhanced the viscosity enhancement of hybrid nano-lubricant. At highest solid volume fraction and temperature, nano-lubricant viscosity was 171% greater compared to pure 20W50. Existed models lack the ability to predict the hybrid nano-lubricant viscosity. Thus, a new correlation regarding solid volume fraction and temperature was suggested with R-squared of 0.9943.