In this work - in view of still decreasing crude oil resources and increasing fuel prices - are presented issues concerning research on development of other, alternative fuel sources including those used in water, land and air transport means. One of them is hydrogen which,while burning, does not produce noxious carbon dioxide but only side effects such as heat and clean water. It is almost true that along with sudden drop of availability and rising price of crude oil many countries face economical paralysis. Any of alternative sources is not capable of supplying even only a basic amount of such energy, not mentioning the whole amount of energy demanded by our civilization. Hydrogen as an independent fuel for internal combustion engines has yet to go a long way to commercialization. to be Co-burning systems (combustion of mixtures )of today used hydrocarbon fuels combined with hydrogen seem closer to this aim. As proved in many investigations the substitution of a part of hydrocarbon fuel by hydrogen enables to make use of beneficial features of both the fuels. One of possible solutions of the problem may be application of an innovative hydrogenic fuel electrolyzer which is presented and evaluated in this paper
Dockside cranes must meet the relevant strength requirements that provide usefulness and not endanger the safety of their use. The vibration effect on structural safety hazard results from the impact of horizontal forces caused by the transport of goods for loading and transverse forces caused by wind, which can be dangerous for correct functioning. In addition, there are often serious effects of climate-related impacts of the environment, material fatigue, which actuates the degradation state of the object. Dynamic loads may therefor cause random effects that devastate the structures or lead to their catastrophic destruction. Recognizing the need to improve the testing methods of crane structures in order to assess their condition and assess their safety factors - this paper attempts to develop a methodology for testing the degradation of the selected portion of a construction crane - using experimental modal analysis, realized in simulation tests in the Inventor environment as well as at test stand research
This article deals with the modeling of the processes of operating both marine main and auxiliary engines. The paper presents a model of changes in operating conditions of ship’s internal combustion engine. The semi-Markov decision process was used to mathematically describe the process model of the engine. The developed model describes the effect of engine damage on the characteristics of its operation.A change in the input parameters of the model can simulate the influence of internal and external factors on the course of the analyzed process. A simplified calculation example is also presented for illustration purposes.The presented method together with developed algorithms and IT tools can be used to solve a wide range of problems related to the operation of marine main engines and other marine equipment as well as maritime and port facilities. This concerns primarily the economic, risk management and operational security issues of complex technical systems, as well as the readiness and reliability analysis of technical facilities
This paper presents a methodology to evaluate the technical state of a Francis turbine by shaft rotor dynamic simulation. There are several rotor dynamic criteria that define the technical state of a turbo-machine. To feed the shaft rotor dynamic model this delivers the required information to accomplish the technical assessment. The numerical rotor dynamic model uses as input, the field forces obtained by the fluid-solid interaction analysis undertaken over the blades of the runner. The rotor dynamic numerical simulations allow to determinate the record-in-time of the displacements of any point along the shaft. This information is relevant for diagnosis tasks, because it is possible to decompose it spectrally and to estimate the severity of the vibrations. Comparing the results of the numerical model against those obtained from machines that operates under normal conditions, it is possible to determinate the technical state of the turbo-machine. This allows studying the stability of the turbine working on several operation ranges. A Francis turbine is a very complex machine that involves many physical phenomena of different nature. In this way, the hydraulic input forces needed by the rotor dynamic model should not be assumed but calculated directly from the fluid interaction over the turbine structure
Ship large-power steam boiler may serve as an example of complex critical technical system. A basis for rational control of operation of such system is knowledge on its capability of fulfilling the tasks to which it was intended. In order to make it possible to apply computer aiding to operational decision-making the capability should be described analytically. In this paper it was proposed to express the capability of ship steam boiler ( considered a complex system) to perform service tasks, by calculating components of its usability potential in a given instant t. To this end , was distinguished a set of steam boiler fundamental features which formulate space of its technical states. Values and characteristic intervals of the features were defined and this way sub-spaces of serviceability and non-serviceability states of the object in question were determined. Next, in the considered space, technical state of the boiler and its usability potential was determined. Owing to this it become possible to quantitatively express the steam boiler functioning capability which served as a basis for elaborating an algorithm for controlling the operational processes of a complex technical system under action. In this paper is also described a way of application of the presented method to calculation of ship steam boiler usability potential, which may be especially instrumental in the case of operational control of the boilers of the kind , equipped with interstage reheaters, i.e. those operating with high values of operational parameters