Importance of Preliminary Design for Centrifugal Compressors

Preliminary Design in AxSTREAM

Centrifugal compressors span a number of applications including oil compression systems, gas shift systems, HVAC, refrigeration, and turbochargers. It works by using energy from the flow to raise pressure, using gas to enter the primary suction eye (impeller). As the impeller rotates, the blades on the impeller push the gas outwards from the center to the open end of impeller to form a compression. Compressors are commonly used for combustion air supplies on cooling and drying systems. In HVAC system application, fans produce air movement to the space that is being conditioned. As a key component of an energy cycle, design/performance requirement must be met. While a design can easily be scaled from an existing design through appropriate parameters, a tailored design from scratch to confirm with design requirement for the specific cycle would give a better match and improve overall cycle performance.

There are variants of non-aerodynamic constraints in centrifugal compressor design practice, from frame size to durability and ultimately cost. An optimized impeller design should also ensure that aerodynamic problems associated with the all compressor components are minimized. With all of these (aerodynamic and non-aerodynamic) design constraints, there is no better way to optimize your compressor design than starting from the preliminary step, making sure that your compressor meets your criteria from a one dimensional basis ( a step that is often overlooked in practice).

Preliminary Design in AxSTREAM

While talking about aerodynamics performance, CFD (or computational fluid dynamics) is the most common analysis method that engineers rely on. True that 3D CFD is accurate and gives you a great prediction to your machine performance, but that comes with the price of time, and time equals cost. When comparing this to 1D/2D analysis, bringing in different designs to CFD analysis is significantly more time consuming. Consequently, it should be in the user’s interest to make sure that their design meets the mechanical limitations, surge margins and the best achievable efficiency starting from an earliest phase to minimize engineering time and this is where having a preliminary design tool would be of use.

By utilizing SoftInWay’s preliminary design module, users are able to optimize their design starting from the very first step of design, using a set of assorted boundary conditions, geometrical parameters and taking into account your specified constraints. This feature gives a good initial approximation of the compressor’s flow path, calculated in inverse 1D formulation.

Users will then also be able to pre-screen and filter through thousands of designs using chosen parameters/limitations to select the most appropriate solution. With this technology, the possibility of moving on with a bad or poorly optimized design can be minimized.  Contact the SoftInWay team at to get more information regarding our preliminary design module!

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