Preparation and property of seal coating for gas turbine compressor

Double-layer structure of seal coating which consisted of a Ni5Al bond coating and a Ni25 graphite top coating were prepared on steel substrate of gas turbine compressor cylinder block.Bond coating was prepared by atmospheric plasma spraying and top coating was prepared by flame spraying.The microstructure,mechanical properties and abradability of the coating were characterized by scanning elec-tron microscope(SEM),hardness tester,universal testing machine,thermal shock testing machine and abradability testing machine.The res-ults show that the overall spraying structure of the seal coating is uniform,the nickel metal phase is the skeleton supporting the entire coat-ing,and the coating is well bonded without separation.The seal coating has a bonding strength of not less than 7.7 MPa,excellent thermal stability,and thermal shock resistance cycle numbers at 500℃more than 50;the scratch length,deepest invasion depth and wear amount of the coating increase with rise of test temperature,with almost no coating adhesion,indicating that the seal coating has excellent abradability.

An Innovative Organic Rankine Cycle with Gas-liquid Injector for Pressurization

The organic Rankine cycle （ORC） is an effective way to recycle low temperature exhaust heat but pump for the ORC has several disadvantages such as great difficulty in manufacturing, easily-invited cavitations, low efficiency and high cost. Gas-liquid two-phase injector is a device without moving parts, in which steam is used to drive cold liquid from a pressure lower than the primary steam to a pressure higher than the primary steam. In this paper, the mechanical circulation pump was replaced with a gas-liquid injector. The effect of the evaporate temperature for the system was studied with the organic fluid R123. While this novel ORC can not only improves the energy utilization, but also be suitable for some occasions without power.

Design of a two spool contra-rotating turbine for a turbo-fan engine

Contra-rotating turbines offer enhanced performance over their conventional corotating configurations.In addition,vaneless contra-rotating turbine stages offer lesser stage length along with improved performance.Contra-rotating turbines with a vaned LP stages offer a controlled work-split between the stages over a wider range of operating conditions by maintaining inlet swirl to the second rotor.The objective of the present work is to design an equivalent vaned contra-rotating turbine for an existing co-rotating configuration of a two-spool turbo fan engine.The contra-rotating turbine is designed by retaining the existing flow path and HP turbine,and redesigning the LP turbine for fixed radial distributions of inlet total temperature,pressure and swirl.A comparative study between performance of the co-rotating and contra-rotating turbines is carried out for different speeds.Cascade testing of the LP stator and rotor mean sections was carried out to validate the analysis.The LP stage of contra-rotating turbine exhibits a performance improvement by 2%points at design point,as per flow predictions.The reduced flow deflection in stator row is the primary reason for significant reduction in profile and secondary losses in contra-rotating turbine,which contributed to the performance improvement.A significant reduction of 23%in blade weight and 45% in LP stator vane count is obtained.