Axial compressors are modern and compact turbo-compressors for applications with very large flows. They are used in air applications (in air compression units or as an air compressor in a gas turbine), natural gas services and mixed refrigerant applications (in some large LNG plants).
When a fluid, either liquid or gas, is constrained within the space between two concentric cylinders, one rotating and one stationary, the fluid in the clearance between the two cylinders will be set into circumferential motion.
The root cause analysis of vibration problems related to critical turbomachinery is an engineering science based on what is often referred to as the "First Law of Machinery Diagnostics". The 1st Law states that displacement (vibration) is equal to the summation of the dynamic forces acting on the rotor divided by the complex dynamic support stiffness of the rotor bearing system.
A paper by Klaus Brun and Terence Grimley of SWRI, Rainer Kurz of Solar Turbines, and William Folles at ASME/IGTI, 2014 dealt with ‘Experimental evaluation of the effectiveness of online water washing in gas turbine compressors.’ Below are excerpts from the paper.
A friction bound control valve (right and/or oil sludge in packing) can cause a unit trip during a main oil pump trip if sufficient system oil (because the valve does not immediately close) is not available during the transient event to prevent a low oil pressure unit trip. A fail
LVDTs (Linear Variable Differential Transformers) are very commonly used as position sensors in power plants throughout the world. Working from AC voltages and frequencies not available from power lines, LVDTs require a signal conditioner to provide the necessary operating power. Alliance Sensors Group's model S1A module is a single channel LVDT signal conditioner on the market today. It can operate practically any inductive or LVDT-type position sensor currently in use.
Case of probable structural resonance
During a mechanical run test of an axially split centrifugal compressor, polar plots from the rotor’s Y-direction probe showed an unusual pattern for a healthy machine at steady state running condition.
Who would have thought that the Winsurance field could provide insight into the operations and maintenance of turbomachinery? Yet that is exactly what occurred at the 39th annual Combustion Turbine Operations Technical Forum (CTOTF) Spring 2014 meeting in Palm Beach Gardens, Florida.
To prevent a unit shutdown on low oil pressure, continuously vent the non-operating cooler and filter by installing orificed return lines, and keep the transfer valve bypass fill line opened to ensure warm-up of the cooler and filter prior to transfer, in cold climates. In cold climates (ambient temperatures below 15oC at any time of the year), cool, static oil in the non-operating cooler and filter will cause a transient pressure drop when it is charged on-line.
The monitoring of the operation and record keeping is of utmost importance to the effectiveness of any flushing operation. A dedicated log book for each flushed console should be maintained, and all entries should detail the condition of flushing screens and mode of o
One of the most important pre-start-up operations for an auxiliary system is flushing. The object of flushing is to render the entire auxiliary system free of excessive particles that could enter into critical equipment components, thus causing significant equipment damage.
The OEM line-up for the coming years of long-term growth is clear. The round of consolidation among the big players seems to be over as the power generation industry is coming out of a cyclical downturn and looking ahead to load growth and orders.
Experience shows that pump MTBFs (mean time between failures) are directly related to mechanical seal reliability. It is well known that pump mechanical seal MTBF is the lowest of all machinery components.
Below are excerpts from the paper ‘Performance Improvement of Gas Turbine With Compressed Air Injection For Low Density Operational Conditions’ (by S. Arias Quintero, S. Auerbach, R. Kraft of PowerPHASE LLC) presented at the 2014 ASME Turbo Expo.