[:en]To have a successful application of an ORC system, the availability of an adequate heat source is crucial. In principal every heat-generating process, such as burning fossil fuel, can be taken as a heat source for ORC.
However, the aim is to improve energy efficiency and sustainability of new or existing applications with the focus on waste heat and renewable energy sources.
[:en]In view of the large number of blades in any turbine machine, the existence of unavoidable sources of vibration excitation and the serious consequences of the failure of just one blade, an intimate knowledge and understanding of the vibration characteristics of the blades in their operating environment is essential.
Whether it is caused by a “poor” design, extreme operating conditions or even too much deterioration, turbine failures can occur. In order to help prevent these it is necessary to perform regular maintenance on all parts of the machine and control the conditions at which the turbine is operating at any moment in time as well as performing repairs and retrofits to keep the pieces in good shape.
One way to improve steam turbine efficiency is through better seals. However, when designed incorrectly they can create significant damages and performance losses in the turbine. Sealing steam turbine rotors presents several challenges. Any gap between the rotor and the packing lets the steam escape, dropping the pressure and wasting energy. If the packing ring is too tight, however, the rotor will rub, which creates localized hot spots. Continue reading “Retrofitting – Why Turbine Seals Are Important”→
A number of loss prediction methods exist in turbomachines. Concerning axial turbines, there are at least seven methods just for cascade losses! But there are also loss models developed to predict individual loss components such as secondary, seal and tip clearance losses and more.
Of course depending on the machine and application type, some of the models are more or less applicable to specific cases. But ff the different types of auxiliary losses, which are losses that do not belong to blade cascades and can be classified as whole stage, there are carryover losses.
The choice of the working fluid for any given application is a key issue and should be done based on specific applications to achieve maximal efficiency. For working fluids in ORC, a green energy alternative, there are some requirements to keep in mind:
•Thermodynamic performance Low pump consumption and high critical point
•Positive or isentropic saturation vapor curve Avoid wetness in flow path, i.e. avoid damages of flow path elements
•High vapor density Decrease sizes of equipment (expander and condenser)
•Acceptable pressures High pressures usually lead to higher investment cost and increasing complexity
•High stability temperature Prevent from chemical deterioration and decomposition at high temperatures
With the ongoing movement toward global environmental protection, regulations related to the exhaust emissions and fuel consumption of automobiles are being strengthened. To cope with these requirements, turbochargers are an effective tool to improve fuel consumption and reduce carbon dioxide emissions, by reducing the engine weight and friction loss.
Since a turbocharger supplies compressed air to an engine, it can reduce the engine displacement relative to an atmospheric engine for the same power. Variable geometry turbochargers, which can control the boost pressure according to the engine operating conditions, are becoming increasingly popular, creating a demand for a centrifugal compressor with a wide and stable operational range. Continue reading “At a Glance – Turbochargers”→
Let’s face it, we know the operations of our gas turbines can’t all be perfect, and we’ll run through calculations, feasibility studies and more to pinpoint the exact cause. But before all of that is accomplished, you should keep a list in the back of your mind of what might be causing your loss in performance, based on common factors that affect gas turbine efficiency and more.
What’s a better way to begin our brand new turbomachinery blog then by addressing a common design question about something we are very familiar with – steam turbines?
Many times the question, “How many calculation sections do you recommend for the (insert any number here)-stage steam turbine?” travels through our tech support emails and we always answer our clients with what we think is best practice. Continue reading “Calculating Sections in Steam Turbines”→