Heat Flux Rate Research Articles

Falkner-Skan aspects of a radiating (50% ethylene glycol + 50% water)-based hybrid nanofluid when Joule heating as well as Darcy-Forchheimer and Lorentz forces affect significantly

Falkner-Skan aspects are revealed numerically for a non-homogeneous hybrid mixture of 50% ethylene glycol-50% water, silver nanomaterials Ag, and molybdenum disulfide nanoparticles MoS2 during its motion over a static wedge surface in a Darcy-Forchheimer porous medium by employing the modified Buongiorno model. The Brownian and thermophoresis mechanisms are included implicitly along with the thermophysical properties of each phase via the mixture theory and some efficient phenomenological laws. The present simulation also accounts for the impacts of nonlinear radiative heat flux, magnetic forces, and Joule heating. Technically, the generalized differential quadrature method and Newton-Raphson technique are applied successfully for solving the resulting nonlinear boundary layer equations. In a limiting case, the obtained findings are validated accurately with the existing literature outcomes. The behaviors of velocity, temperature, and nanoparticles volume fraction are discussed comprehensively against various governing parameters. As crucial results, it is revealed that the temperature is enhanced due to magnetic field, linear porosity, radiative heat flux, Brownian motion, thermophoresis, and Joule heating effects. Also, it is depicted that the hybrid nanoliquids present a higher heat flux rate than the monotype nanoliquids and liquids cases. Moreover, the surface frictional impact is minimized via the linear porosity factor. Furthermore, the surface heat transfer rate receives a prominent improvement due to the radiative heat flux inclusion.

Effects of vortex generator on subcooled flow boiling characteristics in micro-channel

Subcooled flow boiling in a micro-channel is a mainstream heat dissipation way for high-heat-flux electronics. This paper presents a new idea to enhance heat transfer of subcooled flow boiling, i.e. accelerating bubble departure from the heating wall of flow channel by inserting a vortex generator; and the effects of vortex generator positions and working fluid conditions on the heat transfer characteristics are experimentally studied. The shape of the vortex generator is helix with the length, pitch, helix diameter and wire diameter of 22.5 mm, 1.8 mm, 1.8 mm and 0.2 mm, respectively. The vortex generator positions in the experiments include the front, the middle and the end of the flow channel; and the working fluid conditions include the mass fluxes of 1000 – 3500 kg m−2 s−1 and the inlet subcooling degrees of 30–50 K. It is found that the vortex generator could accelerate the bubble departure from the wall, and thus enhance the heat transfer in subcooled flow boiling. The maximum increase of the heat transfer coefficient of the all vortex channel is 8.4 × 103 W m−2 s−1, and the maximum increase rate of critical heat flux (CHF) is 21.8%. Furthermore, a new correlation to predict the heat transfer coefficients of vortex enhanced subcooled flow boiling was developed. The predictions by the new correlation could agree with 92% of the experimental data within a deviation of ± 30%, and the average deviation is 13.7%.

Vapor condensation heat transfer on two-tier hierarchical microstructured surface

Condensation heat transfer on the hierarchical microstructured surfaces is simulated using a three-dimensional phase-change lattice Boltzmann method. Parametric effects raised by widely varying primary micropillar spacing, secondary micropillar position and height, surface wettability and subcooling on the condensation heat transfer are discussed in detail. The condensation heat flux first increases but then decreases with the increase of spacing between primary micropillars. Droplets are prone to nucleate on the top sides of primary micropillars with smaller pillar spacing, and they tend to maintain the Cassie‐Baxter state when secondary micropillars are arranged on the lateral sides of primary micropillars. As the height of secondary micropillar increases, the heat flux first increases but then decreases thereafter. When the contact angle rises from 57° to 130°, the state of condensate droplet changes from the Wenzel state to the partial wetting state. It is also found that there exist four types of droplet nucleation sites on the hierarchical microstructured surface: at the bottom of secondary micropillars, at the corner between primary micropillars and substrate, between two adjacent primary micropillars, and at the center of substrate between four primary micropillars. The increase of subcooling is favorable for nucleation, and the heat flux and condensation rate increase in accordance.

A novel advanced absorption heat pump (Type III) for cooling and heating using low-grade waste heat

The heat of low-grade can be used to get cooling and heating simultaneously by using the coupling of two absorption heat pumps (conventional/not conventional). This novel advanced absorption heat pump requires three pressure levels to increase and reduce the temperature of useful heat, where desorption/condensation processes are shared at medium pressure, and the two evaporation/absorption processes are developed at low and high pressure respectively. The aim of this proposal is to study this kind of advanced absorption heat pump (Type III) by using the first and second laws of thermodynamics, to determine the energy and exergy coefficient of performances for the whole system by taking into account three scenarios of heat flux rates for both evaporators. The irreversibility and exergy performances for the main components are determined to improve the exergy coefficient of performance. The understanding of reversible Carnot cycles, and the general relationship of energy coefficient of performances at low, medium, and high temperatures for this proposal are analyzed. This advanced absorption heat pump reaches cooling temperatures from 14 to 20 °C and heating temperatures between 80 and 106 °C using water/lithium bromide as a working solution. The energy coefficient of performance of 0.68 is obtained when the higher thermal load of the cooling evaporator than the heating evaporator.

Numerical study of the thermal behavior of a cylindrical fin formed by two orthotropic media

Numerical solutions are constructed and presented for the thermal distribution, the dimensionless heat flux rate, and fin efficiency for a two-dimensional orthotropic fin of cylindrical geometry formed by two media subject to a convection limit condition on the side surface and at the high fin base, and to a uniform temperature imposed on the other base of the fin. The results are presented and discussed according to the study parameters, radial thermal conductivity ratio, radial Biot number, and axial Biot number for each medium. Many specific cases are obtained from the global solution presented in this work, among others, the temperature distribution and the dimensionless heat flux rate at the base of a single orthotropic or isotropic fin as well as the case of a fin formed by an orthotropic and isotropic media. The findings of the present study demonstrate that the newly proposed fin design significantly improves the dimensionless heat flux rate of the fin compared to the conventional design. This improvement is particularly significant when the axial Biot number of the outer medium is high and the axial Biot number of the inner medium is low, regardless of the ratio of radial thermal conductivities. These results suggest that the proposed fin design is better suited for applications where heat transfer is critical, and the external environment has a high thermal resistance. In addition, the proposed design also provides a more compact geometry, which not only improves the mechanical performance of the fin but also reduces the cost of the material used in its fabrication.

Quenching modes of local flame–wall interaction for turbulent premixed methane combustion in a constant volume vessel

The quenching mode of local flame–wall interaction (FWI) is investigated for its response to different levels of turbulence intensity as well as its effect on quenching distance, wall heat flux, and near-wall reaction. For that, direct numerical simulations of turbulent premixed methane combustion in a constant volume vessel are carried with initial Karlovitz numbers (Ka) of 1.0, 10.0, and 30.0. Local flame–wall quenching positions are identified based on the local fuel consumption speed during the turbulent combustion process, and the local FWI events have been classified into four quenching modes according to the flame–wall geometric relationships of quenching positions, namely head-on quenching (HOQ), oblique-wall quenching, side-wall quenching (SWQ), and back-on quenching (BOQ). The results show that in the case with higher initial Ka, the flame surface shows a more complicated wrinkled structure due to the flame–turbulence interaction. Meanwhile, the local quenching distance defined based on the identified quenching position is strongly influenced by the near-wall flow, and the range of the local quenching mode extends further to BOQ. However, for all three cases, HOQ and near-HOQ modes account for the majority of local FWI. Wall heat flux and heat release rate (HRR) of near-wall reaction yield high values for the FWI under HOQ or BOQ and are low for SWQ. In addition, there is a discrepancy in the near-wall transportation of some species under different quenching modes, which further leads to the difference in FWI-induced near-wall reaction regarding its total and elementary HRR.

Upslope fire spread and heat transfer mechanism over a pine needle fuel bed with different slopes and winds

The surface fire spread involved slope and wind effects are significantly important in wildland fires, while very limited attention has been paid on the heat transfer mechanism, especially for different fire line conditions. This work experimentally evaluates the effects of slope angle (0˚ to 30˚) and wind velocity (0 to 2 m/s) on spread of surface fire over a pine needle fuel bed. Flame length, flame angle, rate of fire spread, fuel consumption rate and heat flux are acquired and quantitatively analyzed. Two different fireline shapes of sheet and inverted ‘v’ are observed and assumed for different wind velocities and slope angles, respectively. The flame length, rate of spread, mass loss rate and heat flux increase with the increasing wind velocity and slope angle, while flame angle and fuel consumption efficiency vary in the opposite way. The extreme fire can be observed with the external manifestations of a steep increase in flame length, rate of spread and heat flux under conditions of larger wind velocity and slope angle, which is similar to an eruptive fire. In addition, the heat transfer of convection and radiation heat flux is quantitatively analyzed with wind velocity and slope angle to explore heat flux control mechanism. Moreover, the modified models of radiation heat flux considering fire line shape are presented, which demonstrates good effectiveness in predicting radiation heat flux by comparing the calculated values and experimental data.

Flow and heat transfer of supercritical hydrocarbon fuel in additively manufactured cooling channels

As additive manufacturing (AM) technology has advanced, an increasing number of aero-engine cooling components are being fabricated by metal AM. However, the effects of the inherent rough surface morphology from using AM technology on the flow and heat transfer characteristics in the cooling channel are unclear. Therefore, this experimental investigation compared the flow behavior and thermal performance of supercritical hydrocarbon fuel between horizontal AM (Rz = 43.1 µm) and conventionally mechanically manufactured (CM) (Rz = 11.7 µm) mini-channels. The effects of system pressure (p), Reynolds number at the inlet (Rein), and heat flux rate (q) on the flow and heat transfer performance were evaluated. The findings indicate that heat transfer is significantly enhanced in the AM mini-channel compared to the CM channel. The thermal acceleration effect is inhibited in the AM channel owing to the rough topography. The non-dimensional roughness threshold of AM hydraulic rough channel is or lower than 2.2%. NuAM increased by approximately 16, but NuCM increased by 5 when the heat flow rate increased from 166 to 273 KW/m2. Furthermore,hAM increased by approximately 4 KW/(m2-k), but hCM only increased by approximately 2 KW/(m2-k) when the Rein increased from 6100 to 15,000. Moreover, both NuAMand NuCM decrease with increasing system pressure. Finally, the correlations between NuAM and NuCM for supercritical hydrocarbon fuel was proposed to support future research and design of aero-engine complex cooling structures.

Layer-by-layer solution-processed two-dimensional graphene oxide–polyethylenimine thin-film coatings for enhanced pool boiling heat transfer

Nanostructured surfaces are promising candidates for improving liquid-vapor phase-change heat transfer, and their simple fabrication can offer rapid screening of optimal surface characteristics where the phase change occurs. However, conventional fabrication techniques involve energy-intensive processes, such as high-temperature and vacuum conditions or harsh wet chemical treatments. Herein, we propose the use of Layer-by-Layer (LbL) solution-processed graphene oxide/polyethyleneimine (GO/PEI) coatings as ultrathin two-dimensional (2-D) functional surfaces on stainless-steel heaters to enhance the pool boiling heat transfer. The LbL deposition processes implementing repetitive contact and removal of positive and negatively charged water-based solutions directly fabricated GO/PEI bilayers on the heater surfaces. GO and PEI serve as the core plane-like 2-D nanostructure and the bonding agent, respectively, whereas the number of LbL cycles precisely adjusts the physicochemical properties. In the ultra-thin LbL coating thickness (< 85 nm), the significant enhancement rates of critical heat flux (∼ 125%) were obtained in comparison with the bare heater substrate when the working fluid was deionized water. The optimal LbL GO/PEI bilayers facilitate water molecule transport through the extended GO interlayer nanochannels and high-density pinholes, whereas the outer and inner surface characteristics, such as roughness, wettability, and thickness, manipulate liquid-vapor transition-detachment, as well as bubble dynamics. The simple yet effective LbL solution-processed coatings can pave the way for the development of diverse functional coatings of hybridized 2-D and polymeric materials for thermal energy management involving liquid-vapor phase-change heat transfer.

Experimental performance evaluation of multiple-effect diffusion stills under high heat flux

Active stills equipped with additional energy supply devices for enhancing productivity can select the amount of heat flux supply. However, most previous studies have been conducted at a heat flux below 1.0 kW/m2, which can be obtained naturally, and only a few investigated heat flux optimization. In this study, the optimal heat flux and feed flow rate of an active multiple-effect diffusion still (MEDS) were evaluated experimentally at a high heat flux above 1.0 kW/m2 to maximize its performance. An MEDS with 15 effects was fabricated, and its performance was investigated according to the feed flow rate under a heat flux range of 1.0–2.5 kW/m2. The results showed that the freshwater production efficiency in terms of performance ratio (PR) increased with heat flux up to 2.18. The MEDS achieved 8.7 kg/(m2·h) at 2.5 kW/m2. The optimal feed flow rate was identified based on the heat flux at which the MEDS exhibited the maximum output. The cost analysis showed that the MEDS using waste heat has a very attractive water cost of 1.0–3.0 $/m3 at high heat fluxes, which is competitive with even other conventional desalination technologies. Therefore, the active MEDS at higher heat flux shows better performance and lower water cost.

Flow thermohydraulic characterization of open diverging microchannel heat sink for high heat flux dissipation

The future fusion reactor puts forward higher demand for the heat dissipation capability of the divertor, which requires to withstand ultra-high heat flux of up to 20 MW/m2. Our previous study demonstrated that microchannel cooling technology is a promising strategy to remove high heat loads on the target plate of the divertor. However, the high pressure drop of the straight rectangular microchannel limits its practical implementation. In this study, we propose an open diverging microchannel heat sink (ODMHS) to reduce the pressure drop under high heat flux and high flow rate conditions. The effects of the width and height of expanding channel on the heat transfer performance and pressure drop were first studied numerically. The results indicated that expanding channel width resulted in a reduction of heat transfer coefficient, whereas the expansion of the channel height led to the enhancement of heat transfer performance. Regardless of the divergence of channel width or height, the enlargement of the channel dimension can effectively reduce the pumping power. Subsequently, experimental tests were carried out in ODMHS with a width ratio and a height ratio of 1.33 and 1.30, respectively. The results demonstrated that the ODMHS can withstand heat flux of up to 15.6 MW/m2 at 3 L/min. This study provides important insights for high heat flux dissipation on the target plate of the divertor by rational design of microchannel structures.

Design and Analysis of Straight and Curved Fins

A series of fins commonly known as heat sinks are adapted in various thermal appliances the computer and other electronic systems, where large chunks of heat generated have to be dissipated. This project is mainly concerned with developing unconventional fins as a substitute to the conventional rectangular fins. Heat Transfer analysis of curved fins was carried out in this work which can be a substitute for a normal rectangular fins as heat sinks. A detailed evaluation of temperature distribution and heat flux rates with heat sinks made up of curved fins is accomplished and compared with the rectangular fins. This objective was fulfilled for three different types of materials mainly copper, aluminium , magnesium. The entire project was done using CATIA platform for modelling and ANSYS for finite element analysis.

Planetary geodynamics and age constraints on circumstellar habitable zones around main sequence stars

AbstractPlanetary geodynamics may have an important influence over planetary habitability and the boundaries of the circumstellar habitable zone (CHZ) in space and time. To investigate this we use a minimal parameterized model of the co-evolution of the geosphere and atmosphere of Earth-like planets around F, G, K and M main sequence stars. We found the CHZ for the present Solar System located between 0.92 and 1.09 au for a 1.0 M$_{\oplus }$Earth-like planet, extendible to 1.36 au for a 4.0 M$_{\oplus }$planet. In the literature, the CHZ varies considerably in width and border location, but the outer edges tend to be more spread out than the inner edges, showing a higher difficulty in determining the outer edge. Planetary mass has a considerable effect on planetary geodynamics, with low-mass planets cooling down faster and being less capable of maintaining a rich carbon dioxide atmosphere for several billions of years. Age plays a particularly important role in the width of the CHZ as the CHZ contracts in both directions: from the inner edge (as stellar luminosity increases with time), and from the outer edge (as planetary heat flux and seafloor spreading rate decrease with time). This strongly affects long-lived habitability as the 5 Gyr continuous CHZ may be very narrow or even non-existent for low-mass planets (&lt;0.5 M$_{\oplus }$) and fast-evolving high-mass stars (&gt;1.1 M$_{\odot }$). Because of this, the mean age of habitable terrestrial planets in our Galaxy today may be younger than Earth's age. Our results suggest that the best targets for future surveys of biosphere signatures may be planets between 0.5 and 4.0 M$_{\oplus }$, in systems younger than the Solar System. These planets may present the widest and long-lived CHZ.

Performance analysis of the evacuated tube counter-flow absorber and direct-flow absorber to optimize the heat extraction rate for high flow rate applications

The evacuated tube collector (ETC) has gained extensive use in low-temperature applications due to its cheapness and high efficiency. The ETC can be used with a concentrator for medium temperature applications, in the range of 140–200 °C. However, the heat extraction rate of the absorber tube is a limitation factor, particularly at higher heat flux and high flow rates. The energy gained is not directly proportional to the concentration factor used. This work thus proposes a counter-flow copper absorber for increasing the heat extraction rate and compares its performance to the conventional direct-flow absorber. The designs are both optimized by varying the absorber diameters, and a material property analysis is done. COMSOL Multiphysics is used for the simulations. The performance of the 2 systems is evaluated using a conjugate heat transfer model at flow rate ranges of 0.02–0.2 kg/s and uniform theoretical heat flux of 1000, 2000, and 3000 W/m2. Analysis of the results indicates that the counter-flow with 0.01 and 0.02 m inner and outer diameter respectively has 4 times more energy gain than the direct-flow with a 0.01 m diameter. Increasing the heat flux by 2 at 0.02 and 0.2 kg/s flow rate increases the temperature by 1.5 and 1.1 for the counter-flow absorber and 1.2 and 1.04 for the direct-flow absorber. Tripling the heat flux at the same flow rate range increases the temperature by 2 and 1.4 for the counter-flow absorber and 1.5 and 1.07 for the direct-flow absorber. The counter-flow absorber is thus the best choice at higher heat flux and high flow rates which are typically required for industrial heating.

An MHD Casson fluid flow past a porous stretching sheet with threshold Non-Fourier heat flux model

The present paper investigates the magnetohydrodynamics Casson fluid flow with porous medium. The Cu-water nanofluid is used to investigate further analytical results. Thermal radiation is considered along with the Cattaneo-Christov heat flux model and then solved analytically, then expresses the closed forms analytical solution in terms of two variables of hypergeometric function. The special form of Appell hypergeometric solutions are closed form of analytical solutions. The results of normalized shear stress at the wall and temperature profile, and rate of heat flux can be analyzed with suitable parameters, Viz., relaxation time parameter, Prandtl number, Radiation parameter, Magnetic parameter, and so on. The newness of the current work's novelty is to explain a solution to issues with stretching sheets on the basis of Appell hypergeometric form and also investigation takes place on a time relaxation parameter. The shear stress fηη0 is also calculated analytically. This problem has many industrial applications and engineering processes, namely glass-fiber production, extrusion of rubber sheets and so on. Finding that an increase in the thermal relaxation parameter and Prandtl number keeps the fluid temperature constant is the primary physical application.

Theoretical and experimental research on flow boiling heat transfer in microchannels for IGBT modules

Two-phase microchannel heat sink has received extensive attention due to its small size, high heat transfer efficiency, good temperature uniformity, and low working fluid charge. Heat flux and mass flow rate are important parameters that affect the heat transfer performance of two-phase microchannel heat sink. For different heat fluxes, if the mass flow rate is not reasonable, dry-out may occur, which will significantly reduce the heat transfer performance. In order to further explore the influence of mass flow rate and heat flux on heat transfer characteristics, the flow boiling heat transfer performance and flow regimes under different mass flow rates and heat fluxes were studied for a two-phase microchannel heat sink using R245fa as the working fluid. The results showed that when the mass flow rate was 100 kg/(m2·s), the boiling heat transfer coefficient of R245fa showed a trend of increasing firstly and then decreasing with the increase of the heat flux. At a higher heat flux, the local dry-out in the microchannels began to appear, and the heat transfer performance decreased significantly. And the higher the heat flux was, the more serious the dry-out was. There was no obvious dry-out phenomenon when the mass flow rate was 150–300 kg/(m2·s) and the heat flux was below 500 kW/m2. The research provided a valuable reference for exploring the influence of the mass flow rate and the heat flux on the flow boiling heat transfer characteristics of the microchannel heat sink.

Simplified modelling of transient upward flame spread on combustible element

This paper presents the development and validation of a simplified model to simulate upward fire growth and flame spread on vertical surface with combustible materials. The model consists of the following main sub-models: a one-dimensional combined heat and mass transfer model perpendicular to the vertical surface to compute gaseous fuel production due to decomposition and combustion of the combustible material, a simplified model to calculate surface heat flux, and a transient flame growth model based on an existing steady state flame model that takes into account transient heat feedback due to combustion. Validation of the model is checked by comparison of the predictions of this model against FDS (Fire Dynamic Simulator) simulation results and experimental results wherever available, including the following: flame growth with variable heat release rates of solid materials under various levels of external irradiation, temperature distribution through thickness of the wall, and propagation of the pyrolysis front. To demonstrate capability of the new model, vertical burning and upward flame spread on 2.4 m high panels of wood and 5.0 m high panels of PMMA are carried out and compared with FDS simulations. The new model calculation results, including propagation of the pyrolysis front, total heat flux and heat release rate are in good agreement with FDS simulation results. However, the new model requires a fraction (a few minutes of CPU time) of that for carrying out the corresponding FDS simulation (CPU time of 2 days).

Heat Transfer of Water Flow Boiling in Nanostructured Open Microchannels

In recent years, the open microchannel has drawn increasing interest, but severe local dryout limited the heat transfer capability of flow boiling. It was anticipated that nanostructures with exceptional capillary wicking abilities would overcome this problem. In this study, blade-like CuO nanostructures were created in the copper open microchannels to experimentally investigate water flow boiling. Experiments were carried out in nanostructured open microchannels (NMCs), and smooth-surface open microchannels (SMCs), as a comparison, were examined under identical operating conditions. Four main flow patterns, including bubbly flow, slug flow, and two kinds of stratified flow, dominated successively in NMCs and SMCs. Although the flow patterns were similar in NMCs and SMCs, the heat transfer coefficient (HTC) of flow boiling was greatly enhanced by nanostructures under conditions of medium and high heat flux, while the nanostructures’ influence on HTC was unnoticeable at low heat flux. At medium and high heat fluxes, the dependence of HTC on heat flux and flow rate indicated the joint contribution of nucleate boiling mechanism and convective evaporation mechanism to heat transfer. The enhanced effect of nanostructures on nucleate boiling and convective evaporation became more prominent as heat flux increased, leading to a higher HTC in NMCs than in SMCs at higher heat flux conditions.

Numerical investigation on mass and heat transfer performance for novel vacuum membrane distillation modules enhanced by semicircular spacers

Semicircular spacers are creatively introduced into the micro vacuum membrane distillation (VMD) modules for the purpose of modifying flowing field, decreasing mass transfer resistance and enhancing water production. A two-dimensional computational fluid dynamics model is developed to conduct the performance evaluation of rectangular micro-VMD modules. Calculated results indicate that novel VMD modules obtain remarkable improvement in terms of transmembrane mass flow rate. Local velocity and vorticity magnitude around the semicircular spacers increase with augment of the dimension of semicircular spacers as revealed in flow performance evaluation. Thermal performance displays that temperature distribution evolves into uniform when the semicircular spacers are introduced and noticeable improvement can be observed in transmembrane heat flux rate, local temperature and temperature polarization coefficient (TPC) performance. Whereas, Nu number varies in a certain range depending on the configuration of semicircular spacers. This paper further discloses the effect of operating parameters on the mass transfer, heat transfer and TPC performance. It is theoretically found that performance of proposed VMD modules is more sensitive to feed inlet temperature rather than feed inlet velocity. In conclusion, semicircular spacers are believed to be effective strategies to enhance performance of micro-VMD modules, with remarkable improvement to flow field, heat and mass transfer.

The optimum conditions for calcium sulfate fouling rate under subcooled flow boiling using Taguchi statistical method

A comprehensive experimental investigation as well as a statistical design of experiment method (the Taguchi method with L16 orthogonal array robust design) was performed in order to measure the heat transfer reduction and fouling rate of CaSO4 aqueous solutions. Moreover, the effects of different variables (flow rate, CaSO4 concentration, heat flux and bulk temperature) were investigated for two heat transfer mechanisms including forced convection and subcooled flow boiling. Each parameter was studied at two levels so that 16 experiments were totally conducted aiming at introducing the best set of conditions in order to resulting the fewer fouling rate of CaSO4. Based on analysis of variance (ANOVA), the percentage contributions of each factor are ranked as follows: (1) concentration (34%), (2) heat flux (24%), (3) flow rate (23%), and (4) bulk temperature (13%). It also verifies that the interaction of heat flux and flow rate has the greater impact rather than other parameters interactions with a contribution of 2.9%. This experimental result optimum conditions with a fouling rate of 2.1 × 104 m2K/kW.min was very close to the predicted value (1.99 × 104 m2K/kW.min). This demonstrates a good consistency between the experimental and the predicted values, with only a 5% deviation, and approves the effectiveness of the experimental design to attain the optimal condition.