Mathematical model of heating system before the melting of the metal suspension upper half in the manufacture of turbine blades GTE

The article presents the developed mathematical model of heating system before the upper half of the metal suspension melting during the technological process of manufacturing the turbine blades in a discrete-continuous casting plant. The relevance of this research is connected with the lack of reliable mathematical model that can predict the distribution of temperature fields and heat flows inside the plant, which have a direct impact on the quality of formed macro - and microstructure in the castings of turbine blades. The currently existing methods of indirect indicators’ estimation carry significant errors in the selection of optimal technological modes of the blade casting process. The developed model makes it possible to predict more accurate the distribution of temperature fields and heat fluxes in the corresponding zones of the casting plant. Thanks to this, it is possible to predict with maximum accuracy the production of blades with a given internal structure, as well as to estimate the amount of volumetric shrinkage and deformation of the casting. The developed mathematical model in production conditions will make it possible to predict casting defects in the form of captivity and failure, reduce labor capacity and increase the productivity of the blade casting process.

Development of Polymeric Membranes Based on Quaternized Polysulfones for AMFC Applications

A series of quaternary ammonium-functionalized polysulfones were successfully synthesized using a chloromethylation two-step method. In particular, triethylammonium and trimethylammonium polysulfone derivatives with different functionalization degrees from 60% to 150% were investigated. NMR spectroscopic techniques were used to determine the degree of functionalization of the polymers. The possibility to predict the functionalization degree by a reaction tool based on a linear regression was highlighted. Anionic membranes with a good homogeneity of thickness were prepared using a doctor-blade casting method of functionalized polymers. The chemical–physical data showed that ion exchange capacity, water content, and wettability increase with the increase of functionalization degree. A higher wettability was found for membranes prepared by the trimethylamine (TMA) quaternary ammonium group. A degree of functionalization of 100% was chosen for an electrochemical test as the best compromise between chemical–physical properties and mechanical stability. From anionic conductivity measurement a better stability was found for the triethylamine (TEA)-based membrane due to a lower swelling effect. A power density of about 300 mW/cm2 for the TEA-based sample at 60 °C in a H2/O2 fuel cell was found.

Optical and Mechanical Properties of Highly Transparent Glass-Flake Composites

In this paper, the dynamic mechanic and optical properties of composites made of Polyvinyl Butyral (PVB) and Micro Glass Flakes (MGF) with matching refractive indices (RIs) are investigated. The composite is produced by a slurry-based process using additional blade casting and lamination. It can be shown that a high degree of ordering of the MGF in the polymer matrix can be achieved with this method. This ordering, combined with the platelet-like structure of the MGF, leads to very efficient strengthening of the PVB with increasing content of the MGF. By carefully adjusting the RIs of the polymer, it is shown that haze is reduced to below 2%, which has not been achieved with irregular fillers or glass fibers.

Scalable graphene oxide membranes with tunable water channels and stability for ion rejection

Graphene oxide membranes with tunable water channels and stability for ion rejections were fabricated by the blade casting technique and cation intercalation.

Predicting the volume shrinkage while manufacturing the GTE turbine blades

The process analysis of manufacturing the castings of turbine moving blades demonstrated that approximately 5% of the blade blanks from a lot are rejected to a considerable geometric distortion of the blade airfoil. The turbine moving blade casting manufactured by the casting method with directed crystallizing may differ in its geometric and dimensional-accuracy parameters from the design model. The casting geometry varies as a result of high temperature and structural shrinkage deformations which are manifested as the hindered volumetric shrinkage and contraction during crystallizing and upon the casting knockout from the ceramic mould. High-temperature deformations may result in contraction of the casting mould and ceramic core shaping the inner blade cooling channels. As a result, to obtain the blade of the geometric form as set by the designer, it becomes necessary to predict the stress-deformed state of the moving blade casting in order to consider the volumetric shrinkage and deformation in advance. Therefore, predicting and considering the total volumetric shrinkage during the manufacture of the moving blade castings ensuring the minimum contraction of the process system “ceramic mould – casting – ceramic core” is a relevant problem for the modern blank production.