The authors propose an analytical method for designing the inlet annular duct for an industrial centrifugal compressor using high-order Bezier curves. Using the design of experiments (DOE) theory, the three-level full factorial design was developed for determination of influence of the dimensionless geometric parameters on the output criteria. Numerical research was carried out for determination of pressure loss coefficients and velocity swirl angles using the software system ANSYS CFX. Optimal values of the slope for a wide range of geometric parameters, allowing minimizing losses in the duct, have been found. The study has used modern computational fluid dynamics techniques to develop a generalized technique for future development of efficient variable inlet guide vane systems. Recommendations for design of the s-shaped annular duct for industrial centrifugal compressor have been given.

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Abstract. The present study provides the overview of Maisotsenko Cycle (M-Cycle) applications for gas cooling in compressor systems. Various schemes of gas cooling systems are considered regarding to their thermal efficiency and cooling capacity. Preliminary calculation of M-cycle HMX has been conducted. It is found that M-cycle HMX scheme allows to brake the limit of the ambient wet bulb temperature for evaporative cooling. It has demonstrated that a compact integrated heat and moisture exchange process can cool product fluid to the level below the ambient wet bulb temperature, even to the level of dew point temperature of the incoming air with substantially lower water and energy consumption requirements. IntroductionGas compression and transportation is one of the most energy consuming technologies in the world. Compressors are a vital link in the conversion of raw materials into refined products. Compressors also handle economical use and transformation of energy from one form into another. They are used for the extraction of metals and minerals in mining operations, for the conservation of energy in natural gas reinjection plants, for secondary recovery processes in oil fields, for the utilization of new energy sources such as shale oil and tar sands, for furnishing utility or reaction air, for oxygen and reaction gases in almost any process, for process chemical and petrochemical plants, and for the separation and liquefaction of gases in air separation plants and in LPG and LNG plants. The economy and feasibility of all these applications depend on the reliability of compressors and the capability of the compressors selected to handle a given gas at the desired capacity [1]. Since, value of specific work for all compressors is determined by several factors as: specific heat ratio k, specific gas constant R, pressure ratio  and inlet temperature T in . As a rule, all the enumerated factors except the inlet temperature are defined by the initial conditions and/or performance specification for the designed compressor. That is why inlet temperature reduction remains the most feasible way to reduce compressors' specific work.There are a lot of approaches to reduce T in value (depending on the place of cooling):