The paper presents the proposal of a leakage prediction method in flange joints, after pipeline deformation, based on FEM (Finite Element Methods). The stages of developing the design are discussed, and a complex, multi-stage method of applying the loads is presented in detail. Moreover, the gasket material data obtained in experiments were used. The paper also presents the results of calculations on a non-uniform stress distribution in the radial direction of the gasket. In addition, it has been shown that the deflection of the pipeline with a minor displacement causes an increase in the diversification of the circumferential pressure of the gasket, and also has a significant influence on the determination of the actual state of stress to which the gasket is subject. Moreover, it was found that the distribution of contact pressure on the deflection of the pipeline has a significant influence on the level of leakage. The results of tests are compared to the results of the numerical calculations of the stress in bolts. By comparing the bolt tension changes obtained by numerical and experiment analyses, it has been shown that the assumptions made in developing the numerical model are correct.

This paper introduces a conceptual framework for the development and implementation of a digital twin specifically designed for the Wały Śląskie Hydroelectric Power Plant. The primary focus is on defining the digital twin concept, addressing critical challenges encountered during its conceptualization, such as incomplete plant documentation, limited real-time data availability, and complexities in system integration. The digital twin architecture developed to address these issues features modular components, including data acquisition, data processing, visualization, and integration layers, emphasizing scalability, adaptability, and secure interoperability. Computational Fluid Dynamics (CFD) simulations and AI-based modeling techniques are integrated into the proposed framework as essential tools, providing critical data inputs for efficiency modeling and operational analysis. The proposed digital twin concept ensures accurate and reliable digital representation, facilitating informed decision-making and efficient operational management within hydropower plants.

The paper present the method of designing a rubber expansion joints, intended for operation in the pressure class 25 bar. During the design used a numerical analysis,which based on the finite element method (FEM). The results from experimental test were used to correctly modeled the rubber or polyamide reinforcement. Basis on the obtained results, the hyperelastic model of the rubber was prepared, then the design of the rubber expansion joint was tested in different load case, i.e tensile or compressive deflection and pressurization.

The paper presents the way of the fatigue life calculation of a cryogenic tank dedicated for the carriers ship application. The independent tank type C was taken into consideration. The calculation took into account a vast range of the load spectrum resulting in the ship accelerations. The stress at the most critical point of the tank was determined by means of the finite element method. The computation methods and codes used in the design of the LNG tank were presented. The number of fatigue cycles was determined by means of S-N curve. The cumulated linear damage theory was used to determine life factor.

Centrifugal pumps are one of the most widely used machines in all branches of industry. For this reason, their efficiency has a significant impact on energy consumption in global industry (about 20%). It is extremely difficult to design low-specific-speed centrifugal pumps at acceptable efficiency levels due to increasing losses in the impeller (hydraulic, volumetric, and mechanical). This article presents the influence of the geometric features of grooves (width, depth), and the number of them, on the operating parameters of the impeller in a centrifugal pump with microgrooves. The principle of operation of this solution involves the passive control of the flow in the boundary layer using rectangular grooves. The grooves are made inside the flow channels of the impeller and are intended to reduce hydraulic losses occurring during flow. This is mainly due to a reduction in losses in the boundary layer. In order to determine the influence of the grooves’ parameters on the energy characteristics of the impeller, numerical calculations and experimental measurements were performed on 15 sets of impellers, which were obtained using experimental planning methods. The CFD calculations were conducted in order to understand the flow phenomena that occur in the impeller with the microgeometry and their effect on a reduction in internal flow losses. Based on the research results, useful guidelines for designing impellers with low-speed characteristics were formulated.

Centrifugal pumps are the most common machines responsible for the increase in hydraulic energy in a piping system. Their proper design, operation, and maintenance have a strong influence on the performance of technological processes carried out in many industrial units. For the ultra-low specific speed (n_q < 10) application, there is no economical reason for these pumps to be used. This is caused by an increase in internal losses in the pump. The article concerns the problem of the hydraulic operation of a new type of labyrinth pump—the radial labyrinth pump (RLP), which is a developed axial unit. The main research method involves the experimental research of hydraulic sets consisting of passive and active discs. The analyses were preceded by dimensional analysis and experimental planning. The study investigates the influence of a chosen structural parameter of both discs on the process of energy conversion obtained in the pump. The influence of parameters such as number, depth and width of the grooves, as well as inlet angle and diameter on the properties of the pump was studied and discussed in detail. The essential novelty of the article is the recognition of the hydraulic performance of the RLP with grooved discs. To extend the scope of the conducted research for the chosen hydraulic sets, a comparison of the mutual cooperation of an active disc with a smooth and grooved passive one was conducted. It was identified that not every geometric relationship of the parameters of the active and passive discs results in an increase in head with respect to cooperation with a smooth passive disc (motionless). The highest head and high efficiencies were obtained for sets with short channels with large inlet diameters—zk12 and zk13—ratios for zk12 d_1ap/d_2ap = 0.78, and for zk13 zk12 d_1ap/d_2ap = 0.81. Based on the obtained results, preliminary recommendations for the construction were made.