[PDF] Surface Temperature Measurements Using A Thin Film Thermal Array eBook

Author : Mark Schepperle
Publisher :
Page : 0 pages
File Size : 14,1 MB
Release : 2022
Category :
ISBN :

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Abstract: Thermal sensors and actuators are usually introduced at/in micro-channels in two ways: first, in an invasive manner through drilled holes which can lead to leakage problems and a change in channel dimensions and second, mounted in a non-invasive manner outside the channel which reduces heat transfer, accuracy, precision and response time. These problems are multiplied as soon as microchannel boiling with associated rapid thermal effects is investigated. Therefore, in this work, a platinum microheater/temperature sensor array has been developed to provide non-invasive, but nevertheless direct heating and temperature measurement at several locations along microchannels. This array comes without the mentioned disadvantages, resulting in ultra-fast response times that are limited only by the measurement speed of the sensor resistance and linear temperature coefficient of resistance. The working platinum area of each element in the array is only 238 nm thick, 0.1 mm wide and 0.5-2 mm long. The structures can be operated in heating and temperature measurement mode simultaneously. They are integrated into microreactors with the working surface as a side wall of a microchannel and in direct contact with the flowing fluid. Since the structures are deposited on transparent Pyrex glass in a cleanroom process, optical observation of two-phase flow boiling processes is possible for flow regime identification. The maximum operating temperature of the Pt microstructures is 450 °C and the linear temperature coefficient of resistance is about 2.98 × 10−3 °C−1. The relative measurement error of temperature measurements is less than 0.05% due to 2.9 μm thick highly conductive electroplated gold pads which form the electrical contact to the Pt microheaters/T-sensors. The platinum heater structures are capable of generating stationary vapor bubbles with a defined size proportional to the applied heating power. They can also predict two-phase flow boiling regimes (e.g. slug flow), vapor bubble length and frequency via the periodic signal of the measured temperature. Furthermore, they allow accurate calculation of heat transfer coefficients using the exact fluid temperatures measured with the Pt structures at the inlet and outlet of the microchannel, rather than analytically calculated values from temperature measurements outside the channel

Author : Tommaso Astarita
Publisher : Springer Science & Business Media
Page : 237 pages
File Size : 31,67 MB
Release : 2012-08-04
Category : Technology & Engineering
ISBN : 3642295088

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Infrared thermography is a measurement technique that enables to obtain non intrusive measurements of surface temperatures. One of the interesting features of this technique is its ability to measure a full two dimensional map of the surface temperature and for this reason it has been widely used as a flow visualization technique. Since the temperature measurements can be extremely accurate it is possible, by using a heat flux sensor, also to measure convective heat transfer coefficient distributions on a surface making the technique de facto quantitative. This book, starting from the basic theory of infrared thermography and heat flux sensor guides, both the experienced researcher and the young student, in the correct application of this powerful technique to various practical problems. A significant number of examples and applications are also examined in detail.

Author : Franklin Li Duan
Publisher : Springer Nature
Page : 384 pages
File Size : 34,38 MB
Release : 2023-02-23
Category : Technology & Engineering
ISBN : 9811983941

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This book is about the cooperation of AIAA and IEEE, two major engineering organizations from two distinct focus points of technologies: intelligent aero-engine and electrified aviation. AIAA and IEEE both have their intrinsic needs for each other and their co-working is a must-have in the rest of 21st century. AIAA needs IEEE to become smarter and greener and IEEE needs a much broader scope to enlarge its marketplace and playground. The topics related to AIAA's and IEEE's co-project are highly multi- and inter-disciplinary related and highly goal-oriented. The target audience of this book is IEEE, AIAA members and other related professionals from universities, industries and institutes in the fields of AI-driven smart systems and electric airplanes with the associated new electric aero-engines and mobile aviation electric powers. The key contents When AIAA is Meeting IEEE AIAA vs. IEEE How to interact and what to achieve The mindset analysis of AIAA and IEEE The smarter AIAA The AI - Smart brain, IoT, e-devices The smart sensors for AIAA -scenarios, fabrication, challenges, and testings Electric aviation Versatile, smarter, and green The evolution of aero-engines - pistol, gas turbine, electric aero-engine The integration of aero-engines and aero-craft Delta VTOLer and STOL for B787 Rotatable wing and VTOL operation The RDF jet – a new electric aero-engine The features: small, light, thrust The architecture: motor, fan, jet The principle: rim driven, Tai Chi fan, duct, and jet Aviation electric power grid Energy and weight Battery, LTG, and 3D HK SC