Flotherm Software Research Articles

Structural design and thermodynamic analysis of high heat dissipation on board computers based on VPX architecture

Abstract Due to the excellent compatibility of VPX in the international aerospace embedded specifications, VPX specifications are often employed in the design of payload processors for space applications. This paper introduces the design features of a 3U hot-swappable chassis based on the VPX specification, focusing on overall layout and thermal design. To fully utilize the performance of the VPX platform, a modular design is adopted in the overall layout, allowing different functional modules to be freely combined to meet various requirements. The chassis reserves a position for a computing module, facilitating future expansions. In the thermal design, considering the high-density modules inside the chassis, heat pipes are employed to rapidly transfer heat to the chassis rails and outer shell, enhancing the overall heat dissipation capability. Thermal simulation analysis using FLOTHERM software validates that the optimized thermal design meets the first-level derating standards for spacecraft. The finite element analysis results show that the fundamental frequency of the entire machine is 215 Hz, and all indicators meet the design requirements.

Coupling of flexible phase change materials and servers for improving the security of data centers in emergency situations

Data centers with high-power servers cause massive energy consumption. The service object of each server is different, and the server will change from low-load to high-load when an emergency occurs, which increases heat generation. If the heat cannot be removed timely, the temperature will rise rapidly, affecting the operation and safety of servers. A common method is to change the parameters of the cooling system, which will lead to an exponential increase in energy consumption. In this paper, novel flexible phase change material (FPCM) is used for temperature control of servers. Firstly, paraffin/styrene-ethylene-butene-styrene block copolymer/expanded graphite (PA/SEBS/EG) with high flexibility, high thermal conductivity (0.72 W∙m−1∙K−1) and high enthalpy (184.77 kJ·kg−1) was prepared. Then, PA/SEBS/EG was placed above the server, and the temperature was reduced by 3.29 °C compared to without FPCM at an inlet temperature of 26 °C, and the temperature rising rate can be reduced by above 60 %, indicating that FPCM has excellent thermal management effect. Finally, Flotherm software was used to optimize the sizes and parameters of FPCM, the results show 53 × 51 × 16 mm FPCM with 12 wt% EG can reduce the temperature of 13.74 %, 14.03 %, and 14.61 % compared to without FPCM at 1.25, 1.5, 1.75 times power, respectively, and extend 771 s to exceed 80 °C under 1.75 times power. The lifespan can be increased by 3.53 times, and the cooling demand can be reduced by 24.73 %. This study provides solutions for the safe operation and energy consumption reduction of data centers.

A New cooling system based on Piezoelectric fan

For a control box with concentrated power consumption, high heat generation, and small volume requirements, the paper designed a new piezoelectric fan cooling system. The system used piezoelectric ceramics as the fan blade drive module, could achieve directional, efficient and reliable heat dissipation, ensured stable and safe operation of key components. The composition and characteristics of the new piezoelectric fan module were introduced in detail. The simulation results were compared by Flotherm software based piezoelectric fan module in off and on states.

Analysis and research on the heating principle and causes of over-temperature of wind power converter

In view of the frequent over-temperature faults of ABB wind power converter in the process of using, this paper makes an in-depth study and detailed analysis on the over-temperature faults and solutions and effects of the converter through the analysis of the converter heating principle, technical transformation test, thermal simulation analysis, etc.It is found that there are three main reasons for the converter over-temperature fault which are high operating environment temperature, insufficient ventilation and increased thermal resistance coefficient. The three main causes of the over-temperature fault of the converter are analyzed and the technical modification scheme and operability analysis are put forward. In order to verify the technical modification effect, the operation temperature data of the technical modification unit and adjacent units were collected and compared with FLOTHERM software to simulate the heat change trend of the tower cylinder, and the influence of the scheme on the effect and other parts of the unit was judged. The results showed that the scheme could effectively solve the over-temperature problem of the converter and would not affect the normal operation of the wind turbine.

Research on thermal design control and optimization of relay protection and automation equipment

Relay protection devices and power automation systems are an important product in the power equipment manufacturing industry. They are customarily divided into secondary equipment for the transmission and distribution industry, and are responsible for protecting and controlling the primary equipment of the power grid and measuring the load of the power grid system. Thermal design is a major research topic for the reliability study of relay protection devices. The paper introduces the thermal design process of the relay protection device processing equipment, from the single-chip, module level, etc. to construct and isolate the airway facilities, and uses the FLOTHERM software to simulate the relay protection device model. Thermal simulation can guide the structural design, optimize the structure, make the single-machine structure more reasonable, and the heat dissipation more effective, improving the reliability of the single machine.

Discrete Power Semiconductor Losses Versus Junction Temperature Estimation Based on Thermal Impedance Curves

Loss estimation in power semiconductor components is an important research topic for a long time with various methods that have been proposed in the literature. Although these methods have been implemented and allow estimating the losses with satisfactory results, the junction temperature of the component is generally controlled poorly while it influences the losses. This article presents a dynamic calorimetric method used to estimate the losses in power semiconductor devices, taking into account their evolution as a function of the junction temperature. The proposed method is based on the temperature measurement in a metal block fixed under the component. Through a thermal model based on the notion of thermal impedance, the transient temperature measurement in the block allows determining the losses and the junction temperature of the device. In order to size the test bench and determine the robustness of this method with respect to measurement or implementation uncertainties (heat transfer coefficients and thermal conductivity of materials), thermal simulations were performed using the Flotherm software. Due to the presence of noise in the measurements, post signal processing is also necessary. By applying the chosen setting, a corresponding experiment was conducted to verify the proposed method. This experiment showed promising results for both loss and junction temperature determination.

Simulation of Heat Dissipation in a Closed Enclosure Based On Flotherm

As an important method to measure the reliability of electronic products, thermal simulation is widely used in product life prediction and reliability optimization. In this paper, the relationship between the working temperature and working performance of power components and the importance of thermal simulation analysis are discussed. The basic theory of thermal analysis software Flotherm is expounded. The functional characteristics and application range of Flotherm software are introduced. The chassis power device is designed. The boundary condition setting, grid setting, and result processing of the simulation model are introduced in detail. The results illustrate that the maximum temperature of the power components can be guaranteed within the specified temperature range, which satisfies the temperature requirements for reliable operation.

Exploration of the Reliability of Automotive Electronic Power Steering System Using Device Junction Electrothermal Profile Cycle

This paper focuses on the driving steering load cycle stress-strain, shake, and transient temperature profiles in relation to failure in an automotive electric power steering (EPS) system. A compact EPS control system model was applied to construct a lookup table for the device power loss calculations. The lookup table was used to obtain the full electrothermal profile of a vehicle EPS system converter. An accurate thermal model was introduced using FLOTHERM software and compared with the results from EPS device temperature testing. The transient junction temperature profiles of the device were studied based on the operational cycles of the vehicle EPS system. Finally, an efficient rainflow cycle counting method was introduced to obtain the statistic random transient thermal stress cycles. Miner’s rule was also explored, and the relationship between the accumulated thermal stress damage and material fatigue was used to predict the converter’s reliability.

Design of automotive headlamp with high-power LEDS

A novel vehicle headlamp low beam system is presented. The optical system is composed of three identical cells to ensure enough illumination. A poly-ellipsoid reflector and a aspherical lens are used to concentrate the rays and a baffle is employed to produce the cut-off line. The optical performance shows a good agreement with the requirement for headlamp in Chinese national standard. The smart constant current driver sustains automotive headlamps᾿requirements, moreover it has high power efficiency. The performance of three kinds of cooling systems with different structures are simulated and evaluated by FloTHERM software. Then a loop heat pipes combined with fins cooling system is manufactured for cooling the designed LED headlamp. It can greatly improve the cooling efficiency. Even in the 80°C environmental temperature, it can meet the working requirements of LED headlamp low beam system, so it is a kind of feasible cooling scheme.

Heat Dissipation Design of High Power LED Headlamp

High brightness white light emitting diodes(LEDs) are very promising in many new illumination applications. This paper is to investigate the cooling solutions of a LED heallamp. Air cooling with heat sink were proved to be unsuitable. A cooling method based on heat pipe is adopted which is proved to be effective. Simulations were performed with Flotherm software to investigate the thermal permance.A sample of LED headlamp is fabricated based on the structure of a certain sedan combined headlamp. The testing results are in accordance with the simulation results