Two-Phase Cooling Research Articles

Two-Phase Cooling System for Electric Vehicle Battery Based on a 3D Pulsating Heat Pipe

The primary objective pursued in this research is the creation and thorough evaluation of an inventive cooling system designed to uphold optimal temperatures within the batteries employed in electric vehicles. Nowadays, the prevailing equipment underpinning electrical motion hinges on Lithium-Ion cells. These cells frequently necessitate the expeditious delivery of substantial power, thereby giving rise to a consequential generation of heat. Consequently, there is an emergence of elevated operational temperatures, potentially causing noteworthy declines in battery performance, or, in extreme cases, operational failures. Furthermore, deviating from the recommended temperature range (20–40 °C) significantly expedites the aging process of the battery and elevates the probability of premature malfunction. In response to these crucial challenges, the implementation of a battery thermal management system assumes a pivotal role in maximizing battery efficiency. Within the framework of this investigation, we propose the adoption of a cooling system founded on a three-dimensional pulsating heat pipe as the designated thermal management technology for a battery pack. The preliminary phase of our study involved the assessment of the suggested pulsating heat pipe’s performance. Following this, the efficacy of the pulsating heat pipe is subjected to rigorous scrutiny through practical experimentation on an authentic electric battery. The empirical findings conclusively highlight the substantial cooling capacity of the proposed system, thereby presenting a robust and efficacious solution for the thermal management challenges faced by electric vehicle batteries.

Laser Processed Aluminum Nitride Structures for Enhanced Two-Phase Cooling

Laser Processed Aluminum Nitride Structures for Enhanced Two-Phase Cooling

Advances in Two-Phase Cooling for Next Power Electronics Converters

Advances in Two-Phase Cooling for Next Power Electronics Converters

Assessment of Low Global Warming Potential Refrigerants for Waste Heat Recovery in Data Center with On-Chip Two-Phase Cooling Loop

Assessment of Low Global Warming Potential Refrigerants for Waste Heat Recovery in Data Center with On-Chip Two-Phase Cooling Loop

Study on Flow Resistance Characteristics of Cold Plate in Pump-driven Two-phase Cooling System

This paper summaries and analyzes the study on the two-phase flow pattern in cold plate in pump-driven two-phase cooling system. Based on the experimental system, the inlet and outlet flow resistance of the cold plate under different conditions is tested and analyzed. Through the experiment to get the cold plate in different heat flux, different inlet flow rate state of inlet and outlet pressure value, the relationship between the flow resistance and the flow rate, the flow resistance and heat flux of cold plate are analyzed and summarized. The experiment results show that the outlet pressure of cold plate is basically unchanged under different heat flux of cold plate, while the inlet pressure of the cold plate rises with the increase of the inlet flow rate of the phase change medium. The inlet pressure will accelerate after exceeding a certain critical flow, and the different heat flux has no effect on the flow resistance of the cold plate.

Design and Performance Verification of Pump-Driven Two-Phase Cooling System based on PID Control

The core components of phased array radar have high power density. A pump-driven, two-phase cooling prototype was designed and built for their problems such as high heat consumption and high heat dissipation demand. The results showed that the flow rate through each branch was stable, and the heat dissipation performance was better in the case of PID control compared to the case of a flat-faced tube.

Parametric Investigation on the Electrical-Thermal Performance of Battery Modules with a Pumped Two-Phase Cooling System

The pumped two-phase cooling method is a practical way to dissipate heat from the battery module. The operating parameters of the cooling system should be investigated thoroughly to improve the performance of the battery thermal management system (BTMS). However, the previous BTMS designs only explored the thermal performance and ignored the electrical performance in the battery module. This study designed a pumped two-phase cooling BTMS with the refrigerant of R1233zd. An electrothermal coupled model was established for a series-connected battery module to predict thermal and electrical behavior. The results showed that the pumped two-phase cooling system could obtain excellent cooling performance with low system pressure under 2C discharging condition. The average temperature of the module and the temperature difference among cells could be maintained under 40 °C and 5 K under a 2C discharging rate. A lower saturation temperature, higher mass flux, and higher subcooling degree could enhance heat dissipation for the cooling system based on R1233zd. An increase in the saturation temperature and a decrease in the subcooling degree could enhance the temperature uniformity within the module. The battery consistency was mainly dominated by the temperature difference and deteriorated with a lower average temperature in the pack. The research outcome of this paper can guide the design and optimization of the pumped two-phase cooling BTMS.

Two-Phase Cooling in Cutting Systems

Two-Phase Cooling in Cutting Systems

Experimental and Numerical Study on Pump-Driven Two-Phase Cooling Loop for High Heat Flux Avionics

Experimental and Numerical Study on Pump-Driven Two-Phase Cooling Loop for High Heat Flux Avionics

A Review of Recent Developments in Pumped Two-Phase Cooling Technologies for Electronic Devices

In this review, the heat transfer characteristics of several pumped two-phase electronic cooling technologies are quantitatively examined and compared on the basis of heat flux, coolant temperatures, heat source area, base temperature, and coolant type. Cooling by parallel flow in mini/microchannels, pin fins, spray cooling, and jet impingement are discussed in detail. Chip powers up to 2.9 kW and heat fluxes 910 W/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> were demonstrated. The different surface modification techniques used to enhance heat transfer in all four technologies are also presented. Various coolants used in two-phase cooling applications are also quantitatively compared in terms of heat transfer coefficient (HTC), wall temperature, and heat source area. The current issues and potential research in two-phase cooling were also discussed. Water cooling has really high performance in terms of HTC. However, it is challenging for scientists and engineers to implement two-phase cooling with water at wall temperature lower than 100 °C due to high boiling point of water at atmospheric pressure. Therefore, two-phase cooling with water can be implemented in types of electronics that can tolerate higher junction temperature. Although having lower HTC, due to lower boiling point at atmospheric pressure, dielectric coolant can be a promising solution in two-phase cooling when lower chip temperatures are required. Geometry optimization of heat sinks is a promising research topic and has not been studied extensively considering the geometry parameters and solid–liquid interaction that affect thermal and hydraulic performance.

Experimental Demonstration of Pressure-Driven Flash Boiling for Transient Two-Phase Cooling

This work demonstrates transient cooling for high-heat-flux electronics using pressure-controlled flash boiling. Many advanced electronics packages demand rapid, high-heat flux removal under stringent spatial and temporal constraints such as limited lateral heat spreading area, sharp power delivery transients, and heterogeneous power dissipation among dies. Flash cooling achieved by rapid depressurization of liquid coolant is inherently transient and provides high initial peak cooling that can be used for adaptive cooling demanded by these advanced packages. A coolant loop thermal testbed has been constructed to perform rapid transient thermo-fluid experiments of flash cooling with methanol. This work provides insights into depressurization-based flash incipience, thermodynamic analysis of flash cooling, and the ability to provide transient cooling in two application settings. First, a vapor chamber able to adapt to high initial transients applicable for short-burst applications. Second, a co-designed convective chamber that supports simultaneous power delivery and heat extraction for high-performance wafer-scale systems. A prototype vapor chamber was tested to obtain results for overall cooling and flash incipience experiments. The results demonstrate the efficacy of flash cooling for transient thermal management and highlight directions for further research and necessary data to exploit this technique for future electronics applications.

Experimental Study on the Dynamic Heat Transfer Characteristics of a Mechanically Pumped Two-phase Cooling Loop

The present research designs a mechanically pumped cooling loop system and conducts an experimental investigation on the dynamic heat transfer characteristics of the system. The effects of the start-up heat load and heat load variation on the dynamic characteristics of the system are analyzed. The results indicate that during the start-up period, as the heat load rises, the temperature overshoot and duration time of adjustment decrease, while the pressure oscillation amplitude increases. During the regular operation period, as the heat load increases, the temperature at the evaporator outlet gradually increases until it approaches the saturation temperature and then remains constant. The pressure evolution at the evaporator outlet can be divided into four stages: steady state, drastic oscillation, damped oscillation, and slight oscillation.

Experimental Characterization of Two-Phase Cooling of Power Electronics in Thermosiphon and Forced Convection Modes

Abstract In this paper, we present the results of an experimental study involving low thermal resistance cooling of high heat flux power electronics in a forced convection mode, as well as in a thermosiphon (buoyancy-driven) mode. The force-fed manifold microchannel cooling concept was utilized to substantially improve the cooling performance. In our design, the heat sink was integrated with the simulated heat source, through a single solder layer and substrate, thus reducing the total thermal resistance. The system was characterized and tested experimentally in two different configurations: the passive (buoyancy-driven) loop and the forced convection loop. Parametric studies were conducted to examine the role of different controlling parameters. It was demonstrated that the thermosiphon loop can handle heat fluxes in excess of 200 W/cm2 with a cooling thermal resistance of 0.225 (K cm2)/W for the novel cooling concept and moderate fluctuations in temperature. In the forced convection mode, a more uniform temperature distribution was achieved, while the heat removal performance was also substantially enhanced, with a corresponding heat flux capacity of up to 500 W/cm2 and a thermal resistance of 0.125 (K cm2)/W. A detailed characterization leading to these significant results, a comparison between the performance between the two configurations, and a flow visualization in both configurations are discussed in this paper.

Experimental Characterization of the Heat Transfer in Multi-Microchannel Heat Sinks for Two-Phase Cooling of Power Electronics

This study aims to characterize experimentally the heat transfer in micro-milled multi-microchannels copper heat sinks operating with flow boiling, in the attempt to contribute to the development of novel and high heat flux thermal management systems for power electronics. The working fluid was R-134a and the investigation was conducted for a nominal outlet saturation temperature of 30 ∘C. The microchannels were 1 cm long and covered a square footprint area of 1 cm2. Boiling curves starting at low vapor quality and average heat transfer coefficients were obtained for nominal channel mass fluxes from 250 kg/m2s to 1100 kg/m2s. The measurements were conducted by gradually increasing the power dissipation over a serpentine heater soldered at the bottom of the multi-microchannels, until a maximum heater temperature of 150 ∘C was reached. Infrared thermography was used for the heater temperature measurements, while high-speed imaging through a transparent top cover provided visual access over the entire length of the channels. The average heat transfer coefficient increased with the dissipated heat flux until a decrease dependent on hydrodynamic effects occurred, possibly due to incomplete wall wetting. Depending on the channel geometry, a peak value of 200 kW/m2K for the footprint heat transfer coefficient and a maximum dissipation of 620 W/cm2 at the footprint with a limit temperature of 150 ∘C could be obtained, showing the suitability of the investigated geometries in high heat flux cooling of power electronics. The experimental dataset was used to assess the prediction capability of selected literature correlations. The prediction method by Bertsch et al. gave the best agreement with a mean absolute percent error of 24.5%, resulting to be a good design tool for flow boiling in high aspect ratio multi-microchannels as considered in this study.

Physical Heat Transfer Model of Two-Phase Seasonal Cooling Device

A physical heat transfer model of the vertical vapor-liquid seasonal cooling device (SCD) inserted into soil and filled with Freon is considered. In the model, it is assumed that heat exchange with soil occurs at a constant coolant temperature, which corresponds to Freon phase transition temperature and depends exclusively on Freon properties and gas pressure inside the pipe. At a condenser temperature below the phase transition temperature, the SCD functions as a liquid thermosiphon due to enthalpy variation. The physical model of the vapor-liquid SCD is realized as a module in the TEMPA software package representing an internal heat source. The package is designed to solve non-steady-state thermophysical problems by the enthalpy method while considering phase transitions of the bound moisture.

Design, Fabrication, and Characterization of a Compact Hierarchical Manifold Microchannel Heat Sink Array for Two-Phase Cooling

High-heat-flux removal is critical for the next-generation electronic devices to reliably operate within their temperature limits. A large portion of the thermal resistance in a traditional chip package is caused by thermal resistances at interfaces between the device, heat spreaders, and the heat sink; embedding the heat sink directly into the heat-generating device can eliminate these interface resistances and drastically reduce the overall thermal resistance. Microfluidic cooling within the embedded heat sink improves the heat dissipation, with two-phase operation offering the potential for dissipation of very high heat fluxes while maintaining moderate chip temperatures. To enable multichip stacking and other heterogeneous packaging approaches, it is important to densely integrate all fluid flow paths into the device; volumetric heat dissipation emerges as a performance metric in this new heat sinking paradigm. In this paper, a compact hierarchical manifold microchannel design is presented that utilizes an integrated multilevel manifold distributor to feed coolant to an array of microchannel heat sinks. The flow features in the manifold layers and microchannels are fabricated in silicon wafers using deep reactive-ion etching. The heat source is simulated via Joule heating using thin-film platinum heaters. The on-chip spatial temperature measurements are made using four-wire resistance temperature detectors. The individual manifold layers and the microchannel-bearing wafers are diced and bonded into a sealed stack via thermocompression bonding using gold layers at the mating surfaces. Thermal and hydrodynamic testing is performed by pumping the dielectric fluid HFE-7100 through the device at a known flow rate, temperature, and pressure at different levels of chip heat input. A volumetric heat density of up to 2870 W/cm3 is dissipated at a chip temperature less than 112 °C and microchannel pressure drop less than 27 kPa. The overall pressure drop is governed by flowing through the manifold, rather than the microchannels, in this compact heat sink that occupies envelope of 5 mm $\times 5$ mm $\times2.3$ mm including all the functional flow features.

Development of a Numerical Tool for Dynamic Simulations of Two-Phase Cooling Systems

Development of a Numerical Tool for Dynamic Simulations of Two-Phase Cooling Systems

Comparison of the Heat Transfer Capabilities of Conventional Single- and Two-Phase Cooling Systems for an Electric Vehicle IGBT Power Module

This paper presents a comparison of conventional single-phase water/glycol liquid and innovative two-phase cooling technology for thermal management of high-power electronics automotive insulated-gate bipolar transistor modules during a full drive cycle. The proposed two-phase cooling system is built using conventional automotive air conditioning components (a condenser, an expansion valve, a compressor, and vapor and liquid lines) and a conventional cold plate as used for single-phase cooling; thus, the design does not require the development of new technology for its implementation. Three-dimensional numerical simulation in COMSOL and experimental results of two-phase cooling have been obtained on a prototype and compared to conventional water/glycol cooling high-power electronics modules, with a considerable improvement on working temperature, power transfer capacity, and equalization of die temperatures during a full driving cycle. These results suggest that two-phase cooling using the same cold plates as in single-phase cooling can be used to substantially improve the performance and reliability of electric vehicle power converters without major changes.

Mill with Autonomous Two-Phase Cooling

A composite mill with single-use cutting inserts is considered. This mill is intended for dry cutting. Instead of traditional cooling of the cutting zone by means of lubricant fluids, this mill relies on autonomous tool cooling by phase transitions of the first kind (evaporation and melting). Operational tests show that the temperature in the cutting zone and hence the tooth wear decrease when using this mill.

Embedded Two-Phase Cooling of High Flux Electronics Via Press-Fit and Bonded FEEDS Coolers

The increasing heat densities in electronic components and focus on energy efficiency have motivated utilization of embedded two-phase cooling, which reduces system-level thermal resistance and pumping power. To achieve maximum benefit, high heat fluxes and vapor qualities should be achieved simultaneously. While many researchers have achieved heat fluxes in excess of 1 kW/cm2, vapor qualities are often below 10%, requiring a significantly large amount of energy spent on subcooling or pumping power, which minimizes the benefit of using two-phase thermal transport. In this work, we describe our recent work with cooling devices utilizing film evaporation with an enhanced fluid delivery system (FEEDS). The design, calibration, and experimental testing of a press-fit and bonded FEEDS test section are detailed here. Heat transfer and pressure drop performance was characterized and discussed. With the press-fit Si test chip, heat fluxes in excess of 1 kW/cm2 were obtained at vapor qualities approaching 45% and a coefficient of performance (COP) approaching 1400. With the bonded SiC test chip, heat fluxes in excess of 1 kW/cm2 were achieved at a vapor quality of 85% and heat densities approaching 490 W/cm3.