Browse Topic: Coolants
Balancing low conductivity, corrosion resistance and optimum heat transfer in next-generation EV coolants while meeting new EV safety regulations. Managing the heating and cooling of electric vehicle propulsion systems may seem to be an easy task compared with combustion engines. After all, ICEs run much hotter-the thermal optimum for a gasoline engine is around 212 F (100 C). By comparison, EV batteries normally generate (as a function of current during charge/discharge cycles) a relatively cool 59-86 F (15-30 C). And while motors and power electronics operate hotter, typically 140-176 F (60-80 C), they still run cooler than ICEs. But among the myriad complexities of EV thermal management are batteries' dislike for temperature extremes, new cell chemistries, heat-generating high-voltage electrical architectures and 800V fast charging. All are putting greater focus on maintaining stable EV battery thermal performance and safety. Experts note that compatibility among the cell chemistry
Innovators at NASA Johnson Space Center have developed an adjustable thermal control ball valve (TCBV) assembly which utilizes a unique geometric ball valve design to facilitate precise thermal control within a spacesuit. The technology meters the coolant flow going to the cooling and ventilation garment, worn by an astronaut in the next generation space suit, that expels waste heat during extra vehicular activities (EVAs) or spacewalks.
This test method provides a standardized procedure for evaluating the electrochemical resistance of automotive coolant hose and materials. Electrochemical degradation has been determined to be a major cause of EPDM coolant system hose failures. The test method consists of a procedure which induces voltage to a test specimen while it is exposed to a water/coolant solution. Method #1, referred to as a “Brabolyzer” test, is a whole hose test. Method #2, referred to as a “U” tube test, uses cured plate samples or plates prepared from tube material removed from hose (Method No. 2 is intended as a screening test only). Any test parameters other than those specified in this SAE Recommended Practice, are to be agreed to by the tester and the requester.
Hypersonic flight vehicles have potential applications in strategic defence, space missions, and future civilian high-speed transportation systems. However, structural integration has significant challenges due to extreme aero-thermo-mechanical coupled effects. Scramjet-powered air-breathing hypersonic vehicles experience extreme heat loads induced by combustion, shock waves and viscous heat dissipation. An active cooling thermal protection system for scramjet applications has the highest potential for thermal load management, especially for long-duration flights, considering the weight penalty associated with the heavier passive thermal insulation structures. We consider the case of active cooling of scramjet engine structural walls with endothermic hydrocarbon fuel. We have developed a semi-analytical quasi-2D heat transfer model considering a prismatic core single cooling channel segment as a representative volume element (RVE) to analyse larger-scale problems. The model includes
In this paper, we present a novel algorithm designed to accurately trigger the engine coolant flow at the optimal moment, thereby safeguarding gas-engines from catastrophic failures such as engine boil. To achieve this objective, we derive models for crucial temperatures within a gas-engine, including the engine combustion wall temperature, engine coolant-out temperature, engine block temperature, and engine oil temperature. To overcome the challenge of measuring hard-to-measure signals such as engine combustion gas temperature, we propose the use of new intermediate parameters. Our approach utilizes a lumped parameter concept with a mean-value approach, enabling precise temperature prediction and rapid simulation. The proposed engine thermal model is capable of estimating temperatures under various conditions, including steady-state or transient engine performance, without the need for extra sensors. Moreover, it exhibits greater robustness compared to temperature estimation systems
Items per page:
50
1 – 50 of 1366