Cooling Fan Model for Thermal Design of Compact Electronic Equipment: Improvement of Modeling Using PQ Curve
01 Jan 2009-pp 221-228
TL;DR: In this article, the authors used the measured PQ curve to compare the result of the simulation to the experimental data and found that the major reason behind the disagreement was the difference in the pressure definition of the fan model from the pressure measured using a chamber.
Abstract: In order to hasten the thermal design for forced convection electronic devices, cooling fans should be modeled to reduce a computational load. A fan-curve-model, which generates volumetric flow rate versus the characteristics pressure difference of a fan, is very simple and usually incorporated into commercial CFD codes. However, this model often results in an erroneous flow rate. In this work, both the experiments and the CFD simulation were performed around small axial-flow-fans of 30 and 40 mm in diameter. The measured PQ curve was applied to the fan model, and compared the result of the simulation to the experimental data. It was clarified that the major reason behind the disagreement was the difference in the pressure definition of the fan model from the PQ curve measured using a chamber. Based on this, a simple method was proposed to correct this definition. Also, the system effect, which is the impact of obstacles on the fan delivery curve, was investigated by setting a cylindrical obstacle at upstream or downstream proximity of the fan.Copyright © 2009 by ASME
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TL;DR: In this paper, a nonlinear model of the cooling fan system is derived from blade aerodynamics with a driving motor, and a discrete model is applied based on the bilinear transformation of the description of the dynamic behavior and is further used for the least square (LS) parameter estimation.
Abstract: In many industrial fields, cooling fan systems have been widely implemented in electronic equipment such as network hosts, product line junction boxes, manufacturing facilities, computer numerical control (CNC) machine systems, cooling units of array servers, and many other power systems. These systems usually require high computation power and release high heat. Once the cooling fan systems malfunction or the cooling efficiency degrades, it could result in lower system performances or even cause serious damage to the core systems. Thus, there is a growing interest in monitoring and detecting the cooling fan operation status. As a result, the status of the cooling fan systems needs to be monitored in real-time. In this article, dynamics modeling, parameter identification, and online fan speed monitoring of a cooling fan system are presented. First, the nonlinear model of the cooling fan system is derived from blade aerodynamics with a driving motor. Next, a discrete model is applied based on the bilinear transformation of the description of the dynamic behavior and is further used for the least-square (LS) parameter estimation. To suppress the measurement noise, a regulation filter (RF) is further presented to improve the parameter identification precision. In addition, a Levenberg–Marquardt (LM) optimization is further applied for parameter refinement. Simulation comparison studies are considered to validate the proposed method. Moreover, many experiments are conducted to verify the feasibility and reliability for different types of fans. Unlike common conventional monitoring methods, the proposed framework does not apply constant threshold or need any training stages. The alarm threshold is adjusted automatically according to the current operation status. Finally, an embedded measurement and monitoring instrument is developed for demonstrating the effectiveness of the proposed method. Experiments firmly verify the novelty of the model-reference-based online cooling fan monitoring techniques.
13 citations
TL;DR: In this paper, the authors carried out thermal design and evaluated the cooling performance of power electronic devices (PEDs) containing electronic equipment, and the experimental results rove the effectiveness of numerical simulation and electronic equipment cooling scheme.
Abstract: Received: 5 January 2021 Accepted: 11 March 2021 In electronic equipment, thermal failure and thermal degradation are two increasingly prominent problems of the devices, with the deepening integration and growing power density. Currently, there are relatively few reports on the heat transfer mechanism, heat source analysis, and numerical simulation of electronic equipment containing power electronic devices (PEDs). Therefore, this paper carries out thermal design and evaluates the cooling performance of PED-containing electronic equipment. Firstly, the basic flow was given for the thermal design of PED-containing electronic equipment; the heat transfer mode of PEDs and the equipment were detailed, so was the principle of thermal design; the cooling principles were introduced for ventilation cooling, heat pipe cooling, and closed loop cooling. Then, numerical simulation was carried out on the solid and liquid state heat transfer of PEDs and the equipment under different cooling modes. Based on an engineering example, the cooling scheme was finalized through heat source analysis on the proposed electronic equipment. The experimental results rove the effectiveness of numerical simulation and electronic equipment cooling scheme. The results provide a reference for the cooling scheme design for other fields of thermal design.
3 citations
Cites background from "Cooling Fan Model for Thermal Desig..."
...Thus, it is especially important to make a reasonable and effective cooling design for electronic equipment [11-14]....
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01 Nov 2013
TL;DR: In this article, the effect of the obstruction placed in front of the micro blower on the P-Q performance of a piezoelectric micro-blower was investigated.
Abstract: This study describes a performance characteristic of a piezoelectric micro blower which may be available for a novel cooling technology of portable electronic equipment. We especially focus on the investigation whether the micro blower is available for a cooling method of high-density packaging electronic equipment or not. In this paper, the effect of the obstruction, which simulates the electrical components and is mounted very near the blower, on the P-Q characteristic was investigated. Especially we tried to measure the performance characteristic of the micro blower when the obstruction was mounted in front of the blower. From the experiment, it is found that the performance characteristic of the proposed micro blower is almost not changed regardless of the existence of the obstruction in front of the blower. There is a possibility that this novel blower can achieve a high cooling performance regardless of a packaging density of electronic components in electronic equipment.
3 citations
TL;DR: In this paper, the authors describe the performance of cooling fans in terms of the P-Q curve and the maximum flow rate under various environmental conditions, focusing on the relationship between fan performance and configuration factors such as the electronic enclosure.
Abstract: This study describes the performance of cooling fans in terms of the P–Q curve and the maximum flow rate under various environmental conditions. It focuses on the relationship between fan performance and configuration factors such as the electronic enclosure. The presence of an enclosure wall increased the pressure characteristic of the fan performance. The presence of a narrow inlet decreased the flow rate. When the inlet area of the enclosure became smaller than twice the fan flow area, the flow rate was decreased. The maximum flow rate depended on the ratio of the inlet area to the fan flow area. A model for predicting pressure rise and flow rates in the enclosure is proposed. The model is used in a thermal analysis of a PCB model set in an enclosure. © 2011 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.20347
2 citations
01 Jan 2018
TL;DR: In this article, the swirl force acting on the flow was modeled mathematically by introducing a non-dimensional “swirl coefficient,” which can be incorporated into the fan curve model.
Abstract: To hasten the thermal design for forced convection electronic devices, cooling fans should be modeled to reduce a computational load. A fan curve model, which generates the volumetric flow rate according to the PQ curve, is very simple and usually incorporated into commercial CFD (computational fluid dynamics) codes. However, the conventional model does not specify the flow field at the exit of a fan since the PQ curve has no information on the swirl flow. Thus, in this work, the swirl force acting on the flow was modeled mathematically by introducing a non-dimensional “swirl coefficient,” which can be incorporated into the fan curve model. The swirl coefficient was evaluated using a detailed CFD simulation, which takes the rotating blades into account, and the result indicates that this coefficient can be treated as a constant regardless of the radial position of the blade. Subsequently, the flow behind the fan was simulated using the fan curve model incorporated with the swirl coefficient. As a result, it was confirmed that a realistic velocity distribution could be generated within the normal usable range of the fan where the rotating stall does not occur.
1 citations
Cites background or methods or result from "Cooling Fan Model for Thermal Desig..."
...Problem 1) can be easily solved by correcting the pressure definition of the PQ curve, as presented in the literature [1], [4]....
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...2, and a uniform static pressure was applied to the inlet and exit of the computational domain, corresponding to the measurement of the PQ curve [4]....
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...3 shows the generated flow rate Q versus pressure difference ΔP between the inlet and exit of the computational domain, which was compared with the PQ curve obtained experimentally [4]....
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