Robert Smusz

Modelling of Dynamic Temperature States in Layer Microelectronics Systems

The theoretical analysis (compared with experimental investigations) of dynamic temperature states in layer microcircuits (made in LTCC or HTCC technology) has been described in the paper. Two basic models and solution procedures of analytical equations system have been presented. Furthermore their basic advantages and disadvantages have been compared together with accuracy discussion. The solution of the analytical model (for the typical thick-film structure - active layer placed on alumina substrate) has been compared with the experimental results. The many factors which have influence on accuracy of obtained results have been taken into consideration and discussed. The results of analysis can be used in researches with reliability and tolerance aspect of microsystems (intensity of degradation processes) as well as in determination of thermal properties of the designed systems.

Data acquisition system for PW-6U in flight boundary layer mapping

Purpose This paper aims to describe an idea for an integration process and tests of flight parameters measurement system, which supports infrared thermography (IRT) boundary layer mapping. Design/methodology/approach The study of flow changes in the boundary layer with the use of IRT requires registration of the thermal images of the selected area of a wing or the fuselage, as well as synchronous recording of flight parameters. These tasks were realized by the supplementary measurement system mounted on the PW-6U glider. Two examples of the determination of the laminar-turbulent transition areas on the left wing of a PW-6U glider are also presented in the paper. Findings Optical methods can be used in several research areas, for example, aerodynamics and strength analysis. For instance, the measurement of the infrared radiation from surfaces with the use of IRT can be used for the measurement, with high accuracy, of surface temperature distribution. Moreover, the thermography is used for the analysis of the boundary layer. Performed in-flight experiments confirm the possibility of practical usage of the IRT method even on the board of a glider. Practical implications The use of optical methods will, in many cases, be less expensive than assembly of an additional measurement and data acquisition systems. Implementation of optical methods for industrial purposes has many advantages, and, hence, they will probably become very common in the future. Originality/value The study introduces advanced measurement and visualization techniques in general aviation.

Coil Heat Exchanger with the Nanofluid Filled Buffer Layer

The paper presents the preliminary design of the special heat exchanger. The device under consideration is the kind of immersed coil heat exchangers. It consists of three vertical coils: two coils are standard, water is used as a heating medium; one coil is filled by the refrigerant R134a which transfers the waste heat from refrigeration and air conditioning system during the boiling processes. In order to prevent the possible refrigerant leakage, the special buffer layer filled with the nanofluid is mounted in the Freon coil. Thermophysical properties of the nanofluid cause the intensification of the heat transfer through the buffer layer and the same increase of the heat transfer rate. Calculations of thermal power were made. Correlations of heat transfer coefficients in curved tubes, pressure drop correlations for flow through helical coil tubes and correlations describing the heat transfer in the buffer layer, were applied. Results of the calculations indicate of the influence of of Freon coil on the exchanger heat transfer rate. Heat power of Freon coil is about 7 – 25% of water coil thermal power. Thus, the waste heat applied significantly increases the exchanger heat transfer rate.

Implementation of high speed machining in thin-walled aircraft integral elements

Abstract High speed milling (HSM) is currently one of the most important technologies used in the aviation industry, especially concerning aluminium alloys. The difference between HSM and other milling techniques is the ability to select cutting parameters – depth of the cut layer, feed rate, and cutting speed, in order to simultaneously ensure high quality, precision of the machined surface, and high machining efficiency, all of which shorten the manufacturing process of the integral components. By implementing the HSM technology, it is possible to manufacture very complex integral thin-walled aerial parts from the full quantity of the raw material. At present, aircraft structures are designed to mainly consist of integral elements which have been produced by welding or riveting of component parts in technologies utilized earlier in the production process. Parts such as ribs, longitudinals, girders, frames, coverages of fuselage and wings can all be categorized as integral elements. These parts are assembled into larger assemblies after milling. The main aim of the utilized treatments, besides ensuring the functional criterion, is obtaining the best ratio of strength to construction weight. Using high milling speeds enables economical manufacturing of integral components by reducing machining time, but it also improves the quality of the machined surface. It is caused by the fact that cutting forces are significantly lower for high cutting speeds than for standard machining techniques.

Application of high speed machining technology in aviation

Aircraft structures are exposed to many loads during their working lifespan. Every particular action made during a flight is composed of a series of air movements which generate various aircraft loads. The most rigorous requirement which modern aircraft structures must fulfill is to maintain their high durability and reliability. This requirement involves taking many restrictions into account during the aircraft design process. The most important factor is the structure’s overall mass, which has a crucial impact on both utility properties and cost-effectiveness. This makes aircraft one of the most complex results of modern technology. Additionally, there is currently an increasing utilization of high strength aluminum alloys, which requires the implementation of new manufacturing processes. High Speed Machining technology (HSM) is currently one of the most important machining technologies used in the aviation industry, especially in the machining of aluminium alloys. The primary difference between HSM and other milling techniques is the ability to select cutting parameters – depth of the cut layer, feed rate, and cutting speed in order to simultaneously ensure high quality, precision of the machined surface, and high machining efficiency, all of which shorten the manufacturing process of the integral components. In this paper, the authors explain the implementation of the HSM method in integral aircraft constructions. It presents the method of the airframe manufacturing method, and the final results. The HSM method is compared to the previous method where all subcomponents were manufactured by bending and forming processes, and then, they were joined by riveting.Aircraft structures are exposed to many loads during their working lifespan. Every particular action made during a flight is composed of a series of air movements which generate various aircraft loads. The most rigorous requirement which modern aircraft structures must fulfill is to maintain their high durability and reliability. This requirement involves taking many restrictions into account during the aircraft design process. The most important factor is the structure’s overall mass, which has a crucial impact on both utility properties and cost-effectiveness. This makes aircraft one of the most complex results of modern technology. Additionally, there is currently an increasing utilization of high strength aluminum alloys, which requires the implementation of new manufacturing processes. High Speed Machining technology (HSM) is currently one of the most important machining technologies used in the aviation industry, especially in the machining of aluminium alloys. The primary difference between HSM and...