Cooling Fan Speed Research Articles

Design and experimental analysis of a cooling system with erythritol/xylitol PCM thermal energy storage

The erythritol/xylitol eutectic phase-change material has strong potential applications in the field of thermal management. In this study, we propose a cooling system for high-power electronic devices that combined a closed water loop and Latent Heat Thermal Energy Storage (LHTES). The LHTES features double helical coil heat exchange tubes, using erythritol/xylitol as the PCM. A test platform was constructed to evaluate heat transfer performance. During the charging phase, the high-power, high-heat flux heater was cooled using a microchannel cold plate. The heat generated by the heater was transferred to the LHTES. In the discharging phase, the heater was turned off, and the heat stored in LHTES was released, achieving the regeneration of the PCM. Based on our previous work, a method involving gas and seeding injection was employed during the discharging process to trigger secondary nucleation. The helical heat exchange coil not only exhibited good heat exchange performance but also provideed sufficient gas pathways, allowing injected bubbles to create ample disturbance. This ensured thorough mixing of seeding particles with supercooled liquid. The total heat storage capacity of the heat storage unit was 10 MJ, achieving a maximum cooling power of 310 W. The impact of different operational parameters was examined, including water flow rate and heating power during the charging process, and the effects of gas and seed crystal injection, cooling fan speed, and water flow rate during the discharging process. An automated control system was established to optimize the cooling system's operation. This study facilitates the practical engineering application of erythritol/xylitol eutectic PCM.

ANALYSIS OF FAN COOLING SPEED, PRINTING SPEED AND LAYER HEIGHT ON PRODUCT GEOMETRY ACCURACY IN 3D PRINTING

Additive manufacturing is a technology that works by making a product from scratch, layer by layer until it becomes a complete product. An example of additive manufacturing is a 3D printer machine. The process sequence on a 3D Printer machine is the initial stage of creating design drawings in computer-aided design (CAD). Next, materialize the design image into a 3D printing machine. To get the best performance on a 3D printing machine, several parameters are set such as setting the product location during the printing process, setting parameters such as bed temperature and nozzle temperature. Polylactic Acid (PLA) is a filament that is widely used because it is easily decomposed so it is more environmentally friendly, because PLA is made from natural materials such as starch which is used for polymerization. The aim of this research is to determine the effect of variations in fan cooling speed, printing speed and layer height on the accuracy of product geometry in 3D printing using PLA material as well as parameter selection to obtain the most optimal results. The results of this research contained 2 significant factors, namely cooling fan speed and layer height and 1 factor that was not significant, namely printing speed. The percentage contribution of fan cooling speed is 39.52%, printing speed 2.99%, and layer height 11.98%. The optimal variables in this research are level 2 fan cooling speed, namely 100%, level 2 printing speed, namely 70 mm/s, and level 1 layer height, namely 0.1 mm.

Material Extrusion of Helical Shape Memory Polymer Artificial Muscles for Human Space Exploration Apparatus.

Astronauts suffer skeletal muscle atrophy in microgravity and/or zero-gravity environments. Artificial muscle-actuated exoskeletons can aid astronauts in physically strenuous situations to mitigate risk during spaceflight missions. Current artificial muscle fabrication methods are technically challenging to be performed during spaceflight. The objective of this research is to unveil the effects of critical operating conditions on artificial muscle formation and geometry in a newly developed helical fiber extrusion method. It is found that the fiber outer diameter decreases and pitch increases when the printhead temperature increases, inlet pressure increases, or cooling fan speed decreases. Similarly, fiber thickness increases when the cooling fan speed decreases or printhead temperature increases. Extrusion conditions also affect surface morphology and mechanical properties. Particularly, extrusion conditions leading to an increased polymer temperature during extrusion can result in lower surface roughness and increased tensile strength and elastic modulus. The shape memory properties of an extruded fiber are demonstrated in this study to validate the ability of the fiber from shape memory polymer to act as an artificial muscle. The effects of the operating conditions are summarized into a phase diagram for selecting suitable parameters for fabricating helical artificial muscles with controllable geometries and excellent performance in the future.

Analysis and optimization of FFF process parameters to enhance the mechanical properties of 3D printed PLA products

Abstract In this work, the combined effects of fused filament fabrication (FFF) process parameters on the mechanical properties of 3D printed PLA products have been determined by focusing on the tensile strength at R 2 (97.29%). ASTM D638 test standard is used for the preparation of specimens for tensile tests. The optimization technique has been used to determine the optimal combinations of FFF process parameters for the validation of experimental tensile tests and computational fluid dynamics (CFD) simulations. From the results obtained the optimum cooling fan speed of 79.3%, extrusion temperature of 214.4 °C, printing speed of 75.9 mm/s, raster width of 0.4814 mm, and shell number 5 were determined with a 2.266% error of the tensile strength (45.06 MPa). SEM morphology examination shows that the fabricated part cooled at 80% cooling fan speed illustrates good inter-layer bond strength which is also confirmed by CFD temperature distributions analysis.

Facile Route for 3D Printing of Transparent PETg-Based Hybrid Biomicrofluidic Devices Promoting Cell Adhesion.

3D printing has emerged as a promising fabrication technique for microfluidic devices, overcoming some of the challenges associated with conventional soft lithography. Filament-based polymer extrusion (popularly known as fused deposition modeling (FDM)) is one of the most accessible 3D printing techniques available, offering a wide range of low-cost thermoplastic polymer materials for microfluidic device fabrication. However, low optical transparency is one of the significant limitations of extrusion-based microfluidic devices, rendering them unsuitable for cell culture-related biological applications. Moreover, previously reported extrusion-based devices were largely dependent on fluorescent dyes for cell imaging because of their poor transparency. First, we aim to improve the optical transparency of FDM-based microfluidic devices to enable bright-field microscopy of cells. This is achieved using (1) transparent polymer filament materials such as poly(ethylene terephthalate) glycol (PETg), (2) optimized 3D printing process parameters, and (3) a hybrid approach by integrating 3D printed microfluidic devices with cast poly(dimethylsiloxane) (PDMS) blocks. We begin by optimizing four essential 3D printing process parameters (layer height, printing speed, cooling fan speed, and extrusion flow), affecting the overall transparency of 3D printed devices. Optimized parameters produce exceptional optical transparency close to 80% in 3D printed PETg devices. Next, we demonstrate the potential of FDM-based 3D printing to fabricate transparent micromixing devices with complex planar and nonplanar channel networks. Most importantly, cells cultured on native 3D printed PETg surfaces show excellent cell attachment, spreading, and proliferation during 3 days of culture without extracellular matrix coating or surface treatment. Next, we introduce L929 cells inside hybrid PETg-PDMS biomicrofluidic devices as a proof of concept. We demonstrate that 3D printed hybrid biomicrofluidic devices promote cell adhesion, allow bright-field microscopy, and maintain high cell viability for 3 days. Finally, we demonstrate the applicability of the proposed fabrication approach for developing 3D printed microfluidic devices from other FDM-compatible transparent polymers such as polylactic acid (PLA) and poly(methyl methacrylate) (PMMA).

Optimization of Cooling Fan Speed for Heat Transfer Enhancement of Electronic Chip Using CFD

Demand of high-performance personal computers have highly increased today which in turn has increased the need for the efficient cooling system. In heat transfer through forced convection phenomenon, the former depends upon the variation in fluid velocity. The analysis of this paper results that variation in fluid velocity plays a key role in increasing the heat transfer rate and helps to meet the desired cooling environment for the safe performance of electronic components. The fan location is fixed above the chip and fluid velocity is varied and behavior of heat transfer rate is visualized for better design of the cooling system. Simulation has been carried out on ANSYS 15.0 (modeling on ICEM CFD & results from FLUENT). The k-ॉ turbulence model has been applied.

Optimization of immersion cooling performance using the Taguchi Method

Data centers have become one of the most important elements of the Industrial Revolution 4.0. However, conventional data centers face the problem of electricity consumption, with 40% being used for the cooling systems. This led to the proposed development of immersion cooling as one of the methods to solve the current data center cooling system issues. This paper, therefore, was aimed at determining the factors affecting the immersion cooling performance using mineral oil. The experiment was further conducted by creating an immersion cooling box and running the server by loading the software. The contribution and effect of each factor were also determined through the use of the Taguchi Method with Orthogonal Array L8. The performances measured include the CPU temperature and Energy Consumption using the effect of the inlet-outlet location, flowrate and cooling fan speed as the Taguchi factors. The results showed that the CPU temperature was affected by cooling fans with 71.278% and energy consumption by 75.034%.

An experimental study & analysis of effects of different parameters of microwave in production of bio-diesel

A novel and rapid method for transesterifying cottonseed oil into bio-diesel using a domestic microwave oven (MW) has been developed in the present study. Five parameters were investigated to see their effect on bio-diesel yield output. These were input power, reaction time, oil-to-methanol molar ratio, turntable speed, and fan cooling speed. The respective values used for experimentation were 200 W to 500 W, 4 to 11 minutes, 1:4.5 to 1:12, 10 to 40 rpm, and 800 to 1500 rpm and the volume of the catalyst was kept constant at 1%. The experimental results of microwave study were compared to the traditional magnetic stirrer (MS) approach for the same molar ratio and catalyst amount. The optimum parameters for the transesterification process assisted by the domestic microwave oven were obtained such as methanol to oil molar ratio (1:4.5), potassium hydroxide catalyst concentration (1% (w/w)), reaction time (11 minutes), turntable speed (40 rpm) and cooling fan speed (1500 rpm). The corresponding yield of cottonseed bio-diesel (CBD (MW)) was 99.5 percent. Compared with the contemporary MS approach for the same molar ratio and catalyst number, the yield of CBD (MS) was recorded in 25 minutes as 61.23 percent. It was also found that the turntable speed and cooling fan rpm of the improved microwave oven greatly, influenced the yield of bio-diesel and facilitated better utilization of microwave energy in mixing and avoid overheating of the sample mixture. A drastic reduction in microwave input power consumption was observed as compared to the pragmatic MS approach. The findings of this study have established the utility of energy-efficient, updated domestic microwave oven in the generation of bio-diesel on a small scale.

Study on thermodynamic matching optimization of variable flow cooling system of diesel engine at high altitudes

ABSTRACT It is significant to matching optimize of variable flow cooling system for diesel engine at high altitudes, which is helpful to enhance the power and economy, improve the thermal efficiency, and control the heat load of the diesel engine. The experimental design based on the Latin hypercube sampling method was carried out, the collaborative optimization method of variable flow cooling system control parameters based on Genetic Algorithm (GA) was established and the map of cooling fan speed and cooling water pump speed under the condition of variable altitudes (0 m ~ 5500 m) was obtained, which were based on the coupled model of diesel engine and cooling system. Results indicated that as the increase of altitudes, the convective heat transfer coefficient of the air side of the radiator and the cooling fan head decreased, the fan head decreased by 7.24% on average for every 1000 m rise. After optimizing the control parameters of the cooling system at different altitudes, the temperature field of the heated parts was ranked from high to low, which was piston, cylinder head and cylinder liner, and the heat load of the three parts was not over the limit value. Compared with the original engine, after the application of variable flow cooling system, the power and torque of the diesel engine increased, and the higher the altitude was, the more obvious the increase effect was. In the low- and medium-speed region (n ≤ 1500 r/min), the increase effect of the power and torque of the diesel engine increased by 5.27% on average for every 1000 m rise, and the recovery effect was better than that of the high-speed condition. Compared with the original engine, the fuel consumption rate of the diesel engine equipped with variable flow cooling system decreased by 15.88%, and the thermal efficiency increased by 10.99% (percent-to-percent) on average at the altitude of 5500 m.

HydraX, a 3D printed robotic arm for Hybrid Manufacturing. Part II: Control, Calibration & Programming

This part of the study focuses on programming, control and calibration aspects of HydraX, a low cost 6-axis 3D printed robotic arm that performs both Additive and Subtractive Manufacturing. G-code was implemented as the programming language for HydraX, after proper process CAM modeling and code extraction. CAM software post-processor was developed as a Finite-State Machine (FSM), so that NC output files are automatically adjusted, when software input variable values change. Arduino Mega microcontroller has been connected in parallel to the motion controller board of HydraX for expansion of system functionality and enabling the hybrid manufacturing concept. Custom commands (M codes) have also been developed to establish the connection between CAM post-processor and Direct Numerical Control (DNC) software. With these additions, the automatic end effector changer controls the CNC milling spindle, hot end with temperature measurement, filament extrusion and cooling fan speed adjustment, thus leading to successful hybrid manufacturing processes.

Noise Source Identification of Automotive Radiator by Using Sound Intensity Mapping Method

Automotive radiator played an essential role as a heat exchanger that exchange the circulated heated coolant inside the engine compartment to return into its ambient temperature. Radiator cooling fan that attached at the back of radiator, is a device that work to regulate the coolant temperature when the heated coolant is passed inside the radiator tubes. It produces external flow of air that passes through the fins and tubes of the radiator. However, this external flow contributes high noise level into the system. In consequence of this risk, a detailed experimental study on noise analysis to identify the location of maximum sound pressure level (SPL) generated by variations of cooling fan speed by using sound intensity mapping method is presented. Ethylene Glycol (EG)-water based was used as working fluid operate with engine temperature range from 80 to 90 °C. The cooling fan speed of radiator cooling fan were varied from 750 to 1250 rpm and the water flowrates were 8.0, 11.0, and 14.0 l/min. The results indicate that the noise level is increasing with the fan speed. However, there is no significance difference of change in coolant flow rate and type of coolant fluids to the noise level. The location of maximum sound pressure level is identified and the higher SPL value most located on the blade trailing edge of the suction surface with highest SPL value of 81 db for 1250 rpm fan speed. The project delivers the reliable input for the engineering practice to reduce automotive radiator noise level.

The Effect of Change in Flowrate on Power Spectral Density (PSD) of Automotive Radiator System for Flow-Induced Vibration Monitoring

The dynamic motion of internal fluid flow caused an interaction between the fluid’s dynamic forces and a structure’s inner wall. This phenomenon will induce unstable vibration into the system and recently called flow-induced vibration. In this study, an experimental analysis was performed to identify the changes in the characteristics of vibration measured on an automotive radiator resulting from internal flow in a circular heated tube. The vibration result is presented in terms of Power Spectral Density (PSD) that shows the strength of the energy variations as a function of frequency. Water was used as the working fluid operate with engine temperature range from 80 to 90 °C. The air flow velocities of radiator cooling fan were varied from 1.0 to 1.9 m/s and the water flowrates were 2.2, 2.8, 3.2 and 3.8 l/min. Experimental results are presented and indicated that PSD values are dependant to the fluid flowrate. It is also analysed that relationship between vibrations (PSD) and flowrate is influenced by the change of radiator cooling fan speed. Apart from that, the paper also develops a set of vibration features that will assist in identifying low flow conditions in automotive radiator.

Investigation of printable threshold overhang angle in extrusion-based additive manufacturing for reducing support waste

ABSTRACTNotwithstanding the widespread use and large number of advantages over traditional subtractive manufacturing techniques, the application of additive manufacturing technologies is currently limited by undesirable support material waste. Support structures are unavoidable when manufacturing objects with overhangs in extrusion-based Additive manufacturing, leading to extra build time and material waste. In a manufacturing process, different parameters such as cooling fan speed, print speed and print temperature can make a great contribution to printable overhang angle size. In this study, effects of these parameters on printable overhang angle size are studied theoretically and experimentally. First, theoretical analysis of printable overhang is conducted. Then experiments of overhangs with 20°, 30°, 40° and 50° are carried out with regard to different parameters on an FDM printer. According to the results, the printable threshold overhang angle varies substantially with printing conditions. The findings of this paper can then be applied for setting a lower threshold overhang angle for reducing support waste in the future. The findings can also provide some reference for future research in high-precision printing by adjusting relevant print parameters.

Noise and vibration analysis for automotive radiator cooling fan

This paper aims to analyse the noise and vibration of the automotive radiator specifically focused on its cooling fan for different fan conditions and different coolants used namely Ethylene Glycol (EG) water-based and Titanium Oxide (TiO2) nanofluid. Noise source identification is carried out by utilizing the sound intensity mapping method while an accelerometer is used to measure the vibration results. Both of these experiments are conducted when the fan was both in static and working conditions. The maximum cooling fan speed for the working fan detected by a tachometer for EG water-based is 1990 rpm while TiO2 nanofluid is 2030 rpm. The difference in speed is due to the different physical properties such viscosity of each coolant has where TiO2 nanofluid has lower viscosity than EG water-based. The maximum sound power level produced by EG water-based is 53.73 dB while TiO2 nanofluid is 101.94 dB. Meanwhile, the vibration frequencies of EG water-based are higher than TiO2 nanofluid. The noise level increases with the cooling fan speed but decreases with the vibration frequency. Apart from studying the noise and vibration of the automotive radiator, this research also analysed the potential application using nanofluid due to its great properties according to its major use in the heat transfer enhancement. As a conclusion, nanofluid as a radiator coolant could improve heat transfer rate, and could also reduce the presence of vibration in the automotive cooling system.

Temperature Control for a Polymer Electrolyte Membrane Fuel Cell by Using Fuzzy Rule

Temperature control for a polymer electrolyte membrane fuel cell (PEMFC) is important in improving power efficiency and increasing fuel cell lifetime. If the temperature of the cell is too low, then the electrochemical reaction response becomes slow, thereby preventing evaporations of liquid water in the membrane. As a result, cell performance is decreased. However, too high temperature leads to waste in catalyst and heat because of excessive chemical reactions and to liquid water evaporation, which decreases proton conductivity. This study develops an electrochemical dynamical model and a thermal model of a PEMFC using MATLAB/Simulink for simulation. Fuzzy control rules are also built to regulate the temperature of a PEMFC. The fuzzy inputs include temperature error, its derivative, and external load current. The cooling fan speed is chosen as an output variable to regulate the temperature of a fuzzy control because the fuel cell utilizes the air cooling method. After confirming that the designed fuzzy rules are effective for controlling cell temperature, a real experimental device is built using an H-100 fuel cell and a cooling fan to verify the effectiveness of the proposed method.

Heat Sink Cooling Fan and Rotation Speed Effect Analysis on Heat Dissipation of High Power GaN LED Package

In this work, thermal simulation analysis on high power LED is reported where the effect of the heat sink cooling fan and its rotation speed on the heat dissipation of the high power LED was evaluated. Ansys version 11 was utilized for the simulation. The thermal performance of the high power LED package was assessed in terms of operating junction temperature, von Mises stress and thermal resistance. The heat dissipation analysis was done under four types of convection condition:one natural convection conditionthree forced convection condition,. The forced convection condition was used to replicate the effect of a fan with various rotation speeds placed under the heat sink to increase the convective heat transfer coefficient. Results of the analysis showed that that the junction temperature, von Mises stress and thermal resistance of the GaN chip reduces with the increase of the fan rotation speed.

The Formation of Temperature Controller by PSoC

Due to the increasing consumption of energy, the improvement of the cooling system efficiency has become very important. We use programmable system-on-chip (PSoC) to fabricate a temperature control system. These chips include a CPU and mixed-signal arrays of configurable integrated analog and digital peripherals. This system controls the cooling fan speed by temperature detecting. This system uses buzzer and liquid crystal display (LCD) to remind the users. The user can start emergency protection means at once. However, we have designed a controller to control fan speed in according with the difference of measured temperature. This research has the function of power saving and elements protection by reducing to turn on and off a cooling fan. With a simple modification, we can turn any control fan by PSoC control. Today, everybody must use electric appliance. We will use PSoC with temperature-controlled method together to control the cooling device.

Research on the Cooling Fan Speed Control Scheme of the Large Power Vehicular Diesel Engine in Altitude Environment

The cooling water of the large power vehicular diesel engine often got high or low and engine could not work in the adaptive thermal conditions in altitude environment. In order to solve the problem, analyzed the refrigeration requirement of the diesel engine on plateau section, suggested the amelioration program from installing the fluid operated pump-mot fan speed regulating device. Base on the coupling simulation model of the diesel engine working process and coolant system, took the 90°C water temperature of the diesel engine as the optimally target value, analyzed the change canon of cooling fan speed form the ambient conditions and the diesel engine work condition, established the cooling fan rotary speed control MAP on plateau section, and regulated the cooling fan speed by the methods of open loop preset controlling and closed loop feedback controlling. That would provide the improved method for the large power vehicular diesel engine working well on plateau section.

Empirical feasibility analysis of thermoelectric energy harvesting in thermally limited compact mobile computers

Thermoelectric (TE) generation technology was experimentally established in previous research by our group as a viable technique for energy scavenging in a large notebook computer with no significant impact to system performance. The computer under investigation was designed to have additional thermal headroom, with Central Processing Unit (CPU) temperature significantly below its maximum limit under maximum workload conditions. Yet the question remained on if and how such scavenging could be done in small, thermally limited systems, which increasingly represent a larger portion of the contemporary microelectronic products. This paper thus empirically demonstrates the feasibility of thermoelectric energy scavenging in a compact mobile system, where CPU temperature readily reaches the maximum limit as the workload activity is increased. A detailed Finite Element model is presented first for what-if studies. The simulation results from the model are then correlated with the experimental thermal characterization data from a small notebook computer. “Hotspots” as well as the plausible locations for TE integration are identified in the system through the thermal simulations, and are validated by integrating the TE module to the target system. TE power generation density has been measured as 4.27 mW/cm3 under maximum workload conditions with no impact to system performance, as measured indirectly through cooling fan speed, CPU, and integrated graphics temperatures. For a well-characterized off-the-shelf TE component of size 6.05 mm × 6.05 mm × 2.09 mm, the maximum generated power was 410.5 μW, 3.5 times more than the corresponding value measured previously in the large notebook system under the same workload. Harvested power is expected to scale with the system workload activity, and the extension of the current solution to the similar opportunistic locations within the system.

Research on Speed Control Model with Temperature in Hydraulically-Driven Cooling Fan

In order to obtain excellent cooling module, it is necessary to make air flow flowing into the radiator vary with ambient temperature. Cooling fan speed must vary with cooling power continuously. In this paper, the relation was obtained between fan speed and flow, static pressure, torque, power based on calculation and performance test data related to cooling fan. The mathematical model between fan speed and heat dissipation power in cooling module was deduced. Driving characteristics of cooling fan were analyzed.