Car Radiator Research Articles

Temperature-dependent burst failure of polymeric hollow fibers used in heat exchangers

This work analyzes resistance of polyamide hollow fibers used for heat exchangers against extremely high pressures. Hollow fibers made of five different commercially available polyamides and one type of polyphenylene sulfide were tested at different temperatures ranging from −40 to 160 °C. After getting the fiber to the required temperature, pressure from a nitrogen vessel was gradually applied to the lumen side of a fiber until the fiber rupture. The results obtained for different polymers were then analyzed using various burst pressure models used to predict pressure durability of pipelines. The result showed decreasing burst pressure of polyamide fibers mostly from 100 bars to about 50 bars with increasing temperature from −40 to 160 °C. This was contrary to polyphenylene sulfide, which increased from 30 to about 60 bars in the same temperature range. The theoretical models were in a strong disagreement with experimental data and the results fluctuated significantly. However, the fibers showed outstanding durability against rupture no matter of the temperature, since the lowest burst pressure was about 40 bars at 160 °C. From the point of view of practical usability of polymeric hollow-fiber heat exchangers in automotive, the results indicate the polymeric fibers are able to operate at a wide range of conditions characterized by extreme temperature and pressure fluctuations typical for a car radiator.

An insight into the performance of radiator system using ethylene glycol-water based graphene oxide nanofluids

Recent studies showed that nanofluids are considered as a promising way to enhance the heat transfer properties of coolants. Currently, in a car radiator forced convection heat transfer method is carried out to cool circulating fluid. The mixture of water with either ethylene or propylene-glycol is necessary to lower its freezing point and eliminate ice formation. However, the boiling point of deionized water can be pushed up by mixing it with anti-freezing materials like ethylene glycol (EG). Hence the present research work focuses on the heat transfer characteristics of nano-fluids with different combinations of EG and deionized water (60:40, 30:70, and 20:80) along with graphene oxide (GO) nanoparticles (0.1 % wt). The heat transfer potential of graphene oxide/ deionized water-ethylene glycol nanofluids is experimentally investigated in coolant application for car radiators, in which the coolant flow rate is varied from 180 to 420 (LPH) at a fixed coolant temperature of 90 °C. The evaluation of stability is performed using visual inspection and zeta potential test. The density of nanofluid was determined by oscillating U-Tube density meter. The optimized combination of 60% EG, 40% DW and 0.1 wt% GO exhibited higher heat transfer characteristics of the radiator system used. The maximum heat transfer enhancement of 42.77% at 300 LPH, 18.14% at 360 LPH, and 71.1% at 240 LPH for 60:40 EG/DW-based GO nanofluids were obtained. The maximum Nusselt number value of 192 at 420 LPH was observed for 60:40 EG/DW-based GO nanofluid as compared with 20:80, 30:70 EG/DW-based GO nanofluid. It is estimated that by replacing conventional coolant with this nanofluid, reduction in the frontal area of radiator is done which gives more flexibility for industrial design, more eco-friendly vehicle which produces less drag and hence less the fuel cost.

Implementation of Computational Fluid Dynamics and Response Surface Methodology to Study Nanofluid Heat Transfer

AbstractMethods of computational fluid dynamics and design of experiments are implemented in modeling the heat transfer of an Al2O3/water‐ethylene glycol (EG) nanofluid as a coolant in a car radiator system. The main purpose of the study is to propose a model to predict the Nusselt number using the design of computer experiment. The response surface methodology is applied to investigate the effects of the flow rate, the nanoparticle concentration, the water/EG ratio, and the inlet temperature on Nu. Analysis of variance is performed to obtain a suitable correlation that could predict Nu, leading to the elimination of insignificant terms in the initial proposed quadric model and the attainment of a reduced model. Moreover, the reduced model is converted to a simpler linear model using Box‐Cox transformation, which predicts Nu with an accuracy of ±20 %.

CFD Analysis of Enhancement of Heat Transfer of Automobile Radiator with Hybrid Nanofluid as a Coolant

Abstract: The performance of the radiator depends on the fluid used in it as a coolant. The conventional fluids like water, ethylene glycol used as a coolant have low thermal conductivity and are not enough for transferring the heat to more extend. Nanoparticles because of their high thermal conductivity enhances the performance of the radiator when added into the base fluid. In the present work Al2O3-CuO/ Water based hybrid nanofluid is used as a coolant for the CFD analysis of automobile radiator. Different mixing ratios (80:20, 60:40,50:50,40:60 and 20:80) of Al2O3-CuO nanoparticles are used in water with 1% volume concentration. The inlet temperature and volume flow rate of fluid are kept constant. The nanofluid with 20:80 mixing ratio of Al2O3-CuO gives maximum enhancement in heat transfer coefficient and Nusselt number than water by 72% and 65% respectively. Keywords: Coolant, Heat Transfer Coefficient, Nusselt Number, Hybrid Nanofluids, Radiator

Effect of particle size on thermophysical and heat transfer properties of Ag nanofluid in a radiator – an experimental investigation

In this experimental and statistical investigation, Silver (Ag) nanoparticles with varying particle sizes of 20 nm with the base fluid of EG and DI water are tested to improve the heat transfer properties of the car radiator. The thermophysical properties are tested at temperatures varying from 35 to 75 °C. Results showed that small nanoparticles had higher thermophysical properties than large nanoparticles. The heat transfer properties along with friction factor characteristics are measured. A total of 20 nm of Ag has higher thermal transfer properties than other nanofluids; it can be concluded that smaller nanoparticles can improve thermal properties and minimize the radiator size compared to traditional coolants. A systematic optimized RSM-based architecture has been developed to define the quantitative estimate of the specific design parameters influencing nanofluid heat transfer properties and friction factor characteristics. Finally, correlations are developed for experimental Nusselt number and friction factor values by regression analysis.

One-dimension and three-dimension collaborative simulation study of the influence of non-uniform inlet airflow on the heat transfer performance of automobile radiators

• A 1D and 3D collaborative simulation method is proposed for automobile radiator. • The influence of the non-uniform air on the heat transfer performance is studied. • The proposed method predicts the local thermal performance exactly. • Compared to the 1D method, the proposed method has higher simulation accuracy. • Compared to the 3D method, the proposed method saves the time cost by 28.8%. The one-dimensional and three-dimensional numerical simulation methods are traditionally used for heat transfer analysis of radiators, due to the high-efficiency of one-dimensional simulation and the high-accuracy of the three-dimensional simulation, respectively. In the current study, a collaborative simulation method was proposed to combine the advantages of the one-dimensional and three-dimensional methods, in order to investigate the influence of non-uniform inlet airflow on the heat transfer performance of an automobile radiator. In the proposed method, considering that the one-dimensional model cannot directly identify the mapped three-dimensional velocity of the heat transfer unit, the pressure loss coefficient is adopted for transformation. In this way, the application of complex three-dimensional velocity boundaries in the one-dimensional model can be successfully realized. The feasibility of the collaborative simulation method was validated by comparing the errors (0.27 m⋅s −1 and 2.6 °C) between simulated and experimental values of local velocity and local temperature. Besides, compared to the one-dimensional simulation method, the collaborative simulation method had higher accuracy in simulating the local heat transfer on the air side and the coolant side of the radiator. Compared to the three-dimensional simulation method, the collaborative simulation method could save 28.8% of the computational time. The obtained results indicated that the proposed method has a good application prospect in the actual engineering for its satisfactory accuracy and reasonable computational effort.

BİR ISI DEĞİŞTİRİCİSİNDE FARKLI SU-ETİLEN GLİKOL KARIŞIMI KULLANIMININ ISI TRANSFER PERFORMANSINA ETKİLERİNİN DENEYSEL ANALİZİ

In this study, the effects of using different water-ethylene glycol mixture rates on heat transfer performance put in an automobile radiator as a liquid is experimentally analysed. Ethylene glycol is added in water volumetrically and experiments are conducted for 0%, 25%, 50%, 75% and 100% volumetric ratio of ethylene glycol. For all these mixture rates, 300 experiments are conducted for fluid inlet temperature between 40-80 °C, fluid inlet flow rate between 10-22 l/min and cooling air between 1-4 m/s. As a result of the experiments, it is observed that as ethylene glycol mixture ratio passing from the radiator increased, heat transfer decreased. However, as cooling air velocity, fluid inlet flow rate and radiator inlet temperature increased, heat transfer increased as well. When water-ethylene glycol mixture is used in the radiator instead of water, it is observed that radiator fluid freezing temperature decrease and radiator heat transfer performance is negatively impacted.

Automobile Radiator Integrated with Al2O3 Nanofluid for Compact Size and Sustainability Enhancement

Automobile Radiator Integrated with Al2O3 Nanofluid for Compact Size and Sustainability Enhancement

Energetic and Exergetic Assessment of the Cooling Efficiency of Automobile Radiator Using Mono and Hybrid Nanofluids

In this paper, for two separate half-breed Nano liquids, Ag (25nm) + refined water and Ag (50nm) + Zn (50nm)-refined water tentatively considered at the vehicle radiator, the execution of restricted convection. Four distinct cross-breed Nano liquid concentrations in the range of 2-6 vol %. The increase of half breed nanoparticles into the refined water as a base liquid was organized by percentage. Within the range of 20 l/min-60 l /min, the coolant flow rate is altered. Inside the warm trade, Crossover Nano coolants show colossal change compared to the refined water. Ag-refined water cross breed Nano liquid's warm exchange execution was found to be much better than Ag + Zn-refined water half breed Nano coolant. In addition, with the rise in the concentration of half breed nanoparticle and half breed Nano fluid velocity, the Nusselt number is found to expand. In the advancement of the warm exchange rate, Mono and hybrid nanofluid forms play a very important role in enhancing the heat transfer and refrigeration of car radiators. With an increase in concentration of half-breed nanoparticles for the primary form about 44 percent warm exchange transition, expansion of 6 vol percent crossover nanoparticles were achieved with the rate of warm exchange. In comparison to the current form of cross breed nanoparticles, with an expansion of 6 percent vol concentration, 22 percent extended. The exergy in flow, exergy destruction and exergy efficiency of mono nanofluid (Ag +Dw) are greater than hybrid nanofluid (Ag + Zn + Dw) and distilled water. The exergy inflow, exergy destruction, and exergy efficiency as the concentration of nanoparticles increases for the two forms of mono and hybrid nanofluid. The values parameters of the mono nanofluid (Ag + Dw) such as exergy in flow, exergy destruction and exergy efficiency at 6 vol% were 572 W, 460 W, 72% respectively while in hybrid nanofluids (Ag + Zn + Dw) were 420W, 282W, 51%. The use of mono and hybrid nanofluid as a working fluid results in higher efficiency of heat transfer, which promotes the performance of the car engine and decreases fuel consumption.

Radiative heat transfer of nanomaterial on a convectively heated circular tube with activation energy and nanoparticle aggregation kinematic effects

The improvement of the thermal conductivity of the nanoliquid due to the inclusion of a certain amount of nanoparticles is well known. However, the cause of the observed abnormal improvement remains unclear. For this reason, the aggregation kinematics of nanoparticles is significant for evaluating the appropriate thermal effect of particles at the nanoscale. The scope of nanomaterials can be seen in various engineering and industrial fields such as nuclear reactor coolants, heat exchangers, aircraft coolants, microreactor coolants, automobile radiators, solar collectors, etc. Therefore, this study investigates the effects of the aggregation of nanoparticles on radiative nanoliquid flow with activation energy over a horizontal tube subjected to the convective thermal boundary conditions. Experimentally verified correlations of multiwall carbon nanotube aggregation are utilized. The response surface methodology (RSM) is used to determine the optimum levels of the physical parameters to maximize the mass transfer rate of the nanoliquid. The magnitude of the volume fraction and velocity are superior in the absence of aggregation kinematics than in the presence of nanoparticles aggregation mechanism. From the RSM analysis, the maximum Sherwood number obtained is 1.1384 with desirability d = 0.9993. The present results may have applications in nanoliquid-dependent structures, heating/cooling processes, and thermal systems.

Review on Thermal Analysis of Automobile Radiator

Radiators are used to transfer thermal energy from one medium to another for the purpose of cooling. Low efficiency heat exchangers used in automotive as radiator may cause to serious dangers for the engine. Hence, thermal scientists and engineers always pursuit modern methods to enhance the heat removal of the engine. It seems nanofluids implementation in automotive cooling system promises to achieve high efficiency radiators. This paper reviews almost all performed studies in this area that are available in the literature. Author collects details about nanoparticles materials and size, base fluid, volume, concentration, flow regime and Reynolds number used in studies. Usually, maximum heat transfer enhancement and maximum need of pumping power that occurs at the highest volumetric concentration of nanoparticles, simultaneously. On the other hand, using nanofluids, due to the enhanced heat carrying capacity of the nanofluids; the pumping power required will also be reduced.

Heat transfer performance and exergy analyses of MgO and ZnO nanofluids using water/ethylene glycol mixture as base fluid

Forced laminar convective heat transfer of MgO and ZnO nanofluids through flat tube automobile radiator was studied numerically using 0.25-3ć volume concentrations at Reynolds number ranges (250–1750) for both nanofluids. The results showed an increase in the convective heat transfer coefficient 13.76% and 17.1% at 3% concentration of ZnO and MgO nanofluids, respectively, relative to water/ethylene glycol mixture (50:50 by vol%.) as a base fluid. However, increasing the volume concentration caused an increase in the pumping power For same heat rejection of W/EG mixture, a reduction of about 4.15% and 3.1% in radiator surface area was obtained at 1% concentration of MgO and ZnO nanofluids, respectively. A decrease in total exergy destruction rate of 15.7% and 12.2% compared to the base fluid was obtained for 3 vol% of MgO and ZnO nanofluids, respectively, at Re = 1750.

Differential transformation method to determine heat transfer in annular fins

AbstractFins are the extended surfaces that are utilized to afford a significant increase in the surface area for heat transference between a heated source and a colder ambient liquid. To enhance the heat transference rate from the exterior surface of a circular conduit, radial, or concentric annular fins are used. Fins are utilized in heat exchanging devices like superheaters, electrical equipment, computer CPU heat sinks, car radiators, refrigeration, and heat exchangers. Motivated by these applications, the current paper explores the thermal attribute of an annular fin with variable thermal conductivity. The framed equations are articulated in terms of nonlinear ordinary differential equations. One of the most effective techniques, the differential transformation method has been implemented to find the analytical solution. The domination of nondimensional parameters on the thermal gradient of the fin has been analyzed graphically. Furthermore, the variation in radial and tangential stress in an annular fin for various dimensionless parameters has been examined with a graphical explanation. Results reveal that the thermal gradient of fin increases for improved values of variable thermal conductivity parameters. The greater values of thermogeometric parameters result in a higher heat transfer.

Heat transport investigation of magneto-hydrodynamics (SWCNT-MWCNT) hybrid nanofluid under the thermal radiation regime

The prime objective of the present study is to examine the comparison of heat transfer attributes of magnetohydrodynamic hybrid nanofluid flow in the presence of radiation. The phenomenon of generally new standard fluid “hybrid nanofluid”, has been explored to enhance the heat coefficient in the boundary layer flow. Single wall and Multiwall carbon nanotube particles (nanometer in size) have been utilized to constitute the required hybrid nanofluid. The nonlinear system of differential equations is handled through the bvp4c MATLAB algorithm. The Nusselt number increases significantly for lower values of pressure and decreases for higher pressure gradients while keeping the radiation value at zero. The Sherwood number first increases for lower buoyancy parameters and then decreases for higher values, for both hybrid nanofluid cases. The local skin friction decreases for minimum rotation then it increases for higher rotation in both directions, it shows similar behavior for both cases. These hybrid nanofluids can enhance the performance of heat exchangers, electronic cooling, heating in pipes, car radiators, nuclear plants, solar heating. The study suggests exploitation of these fluids can be helpful to reduce the production cost.

Heat transfer enhancement through nanofluids with applications in automobile radiator

This article investigates the heat transfer enhancement on three different types of nanofluids Titanium dioxide(TiO2), (CuO) Copper oxide and Aluminum oxide (Al2O3) using an application in automobile radiator while considering the slip condition. A comparative study has been carried out for all three nanofluids. The governing partial differential equations are reduced into ordinary differential equations by using similarity transformations. It is observed that the high values of Grashof number leads to decrease in thermal performance of the nanofluid and TiO2 nanofluid affected the most. This study shows that the thermal slip effects leads to a decrease in temperature of the fluid. This decrement is dominant in TiO2 nanofluid whereas CuO has shown least effects of slip parameter. Among all three nanofluids, Al2O3 nanofluid shows the best thermal performance.

Performance Comparison of Propylene Glycol-Water and Ethylene Glycol-Water Mixtures as Engine Coolants in a Flat-Tube Automobile Radiator

This study aims at evaluating and comparing the thermal performance of five different engine coolants employed in an experimental engine cooling system with a flat-tube louvered-fin automobile radiator. For this purpose, a PLC-controlled test system was set up. The system could maintain the temperatures of the air and coolant at the radiator inlet, the speed of the air and flow rate of the coolant at the required values during the tests. The tested coolants were pure wa-ter, 30/70 ethylene glycol (EG)/water, 30/70 propylene glycol (PG)/water, 50/50 EG/water and 50/50 PG/water mixtures. In all tests, the coolant temperature at the radiator inlet was kept at 90°C, while the coolant flow rate was varied between 0.10–0.25 l/s with 0.05 l/s increments. Furthermore, the air temperature at the ra-diator inlet was kept at 25, 30 and 35°C, and the air speed passing over the radia-tor was varied between 1–4 m/s with 1 m/s increments. The thermal performance of the radiator was evaluated by locating the measured coolant flow rate and coolant inlet/outlet temperatures into the conservation of energy equation. It was found that water yielded the highest radiator heat rejection rates. Compared with water, 30/70 EG/water, 50/50 EG/water, 30/70 PG/water, 50/50 PG/water mix-tures yielded on average 3.50%, 7.89%, 8.28%, 11.46% lower radiator heat rejec-tion rates, respectively. Since PG has some advantages over EG such as lower cost and toxicity, PG mixtures can be employed as antifreeze instead of EG mix-tures in expense of a slight decrease in the thermal performance.

Effect of Ultralow Concentrated Reduced Graphene Oxide Nanofluid on Radiator Performance

Abstract Nanocoolants are engineered colloidal suspensions of nanoparticles in a conventional coolant (water–ethylene glycol). Use of metals and metallic oxide nanofluids at concentrations greater than 0.01 vol % has been studied in greater detail compared to functionalized graphene nanofluids. In the present work, an experimental investigation is carried out on an automobile radiator by changing the conventional coolant to reduced graphene oxide (RGO) nanocoolant. The present study focuses on the effect of ultralow nanoparticle concentration (0.002–0.006 vol %), Reynolds number of hot coolant (80–170), Reynolds number of air (210–270), and inlet temperature of hot coolant (40 °C and 60 °C). The effect of these parameters on the performance of the radiator is measured in terms of convective heat transfer coefficient (CHTC), Nusselt number, friction factor, and effectiveness. Results indicate that at 0.006 vol % concentration, there is a maximum increase of 100.5% and 111%, respectively, in CHTC and effectiveness, besides a reduction in friction factor. RGO nanocoolant offers great scope for reducing the radiator size and increasing its performance.

Thermal Performance Intensification of Car Radiator Using SiO2/Water and ZnO/Water Nanofluids

Abstract Recent progress in nanotechnology has led to a revolution in the automotive cooling system. In the present work, enhancement of car radiator thermal performance was investigated using different nanofluids namely SiO2/water and ZnO/water nanofluids as cooling mediums. The present study mainly aims to investigate the impact of 5 wt% from SiO2 and ZnO nanoparticles (NPs) dispersed in water based on car radiator heat transfer with spherical and hexagonal morphology, respectively. The experiments were performed in two working conditions of the nanofluids, i.e., coolant temperature and volume flowrate; moreover, the present results were compared with the previous studies. The experimental working conditions were set at coolant inlet temperature (tc,i) ranged from 45 to 80 °C and the coolant volume flowrate (V˙) varied from 3.5 to 6.5 liter/min. The experimental results show that the hexagonal ZnO/water nanofluid was superior toward enhancement of car radiator thermal performance comparing to that of SiO2 NPs. In addition, at 6.5 liter/min and 45 °C, the improvements of car radiator effectiveness due to using SiO2 and ZnO based water nanofluids and compared with that for the based water are 13.9% and 16%, respectively. The present study used the multiple regression analysis (MRA), and hence empirical correlations are suggested to estimate the overall heat transfer coefficient (U) for all coolants as functions of volume flowrate (V˙) and the coolant inlet temperature (tc,i) with a maximum STDEV of ±1.85%.

Integrated Taguchi-GRA-RSM optimization and ANN modelling of thermal performance of zinc oxide nanofluids in an automobile radiator

Impact of different input variables on the thermal performance features of an automobile radiator was investigated, statistically analyzed, and optimized using the powerful technique-Taguchi's grey relational analysis (GRA) and Response surface methodology (RSM). Polyethylene glycol (PEG) nanofluids containing ZnO nanoparticles of various volume concentrations (0.2%–0.6%) were used. 1-Butyl 3-methylimidazolium bromide [C4mim][Br] ionic liquid was added to reduce particle accumulation and increase nanofluid dispersion. The mini radiator used was an unmixed crossflow type. The analyses were carried out at various flow rates. Thermal performance parameters like Nusselt number (Nu), heat transfer coefficient (htc), pressure drop, and pumping power were optimized by using weighted grey relational grade, depending on the experiments designed using Taguchi's Experiment Design. ANN modelling was used to get a better prediction of the non-linear form of critical data. Optimized Nu, htc, pressure drop, and pumping power were obtained for different combination of Re, air velocity, and nanofluid concentration to maximize. The htc estimated by ANN is found to be reasonably consistent with the experimental findings. From the research findings, it is also inferred that heat transfer enhancement does occur in radiators employing nanofluids but at the expense of the pressure drop and pumping power.

A non-linear mathematical analysis of thermally radiative stratified nanoliquid featuring the aspects of magnetic field, Robin conditions and thermal radiation

The heat transportation features of current liquids are improved exceptionally via suspension of nano-sized solid elements having diameter (<100nm) and are regarded as potential working liquids for the utilizations like automobile radiators, electronic chilling systems, solar collectors, heat pipes, nuclear reactors etc. Here in present investigation, nanoliquid model encompassing diffusions (thermophoresis and Brownian) is utilized to address Jeffrey material convected flow under viscous dissipation, thermo-solutal (stratifications, Robin conditions), suction/injection and Joule heating. Hydromagnetic flow persuaded by a permeable cylinder's movement is formulated. Boundary-layer approach is opted to simplify the mathematical systems. Non-dimensionalization process is done through similarity variables. Non-linear analysis is reported by utilizing homotopy concept. Besides the results are provided on physical contextual of involved constraints.