How are compressor maps made?

How are compressor maps made?

Typically, compressor and turbine maps for turbochargers are generated by running a turbo on a properly instrumented gas stand in a test cell. The maps are generally created by running the turbocharger at a constant speed and varying the pressure ratio on the compressor side.

What is compressor performance map?

A compressor map is a chart which shows the performance of a turbomachinery compressor. Compressor maps are an integral part of predicting the performance of gas turbine and turbocharged engines, both at design and off-design conditions.

What is surge margin?

Surge margin. The surge margin (SM) is defined as the distance between the surge line and the operating point on a vertical line for a constant corrected mass flow value. Several definitions are in use to define the SM.

How is Turbo rpm calculated?

Calculating Additional Points: 4200 RPM

1. Our Example:
2. Wa = Airflow actual (lb/min)
3. MAP = Manifold Absolute Pressure (psia) 28.025.
4. R = Gas Constant = 639.6.
5. Tm = Intake Manifold Temperature (degrees F) =130.
6. VE = Volumetric Efficiency 0.80.
7. N = Engine speed (RPM) = 4200 RPM.

How does compressor surge happen?

Surge is a condition that occurs in compressors when the amount of gas they are trying to compress is insufficient for the size of the compressor and the blades lose their ability to transfer energy from the shaft to the fluid, causing a reverse flow of the gas.

What is compressor pressure ratio?

We measure the increase by the compressor pressure ratio (CPR), which is the ratio of the air total pressure pt exiting the compressor to the air pressure entering the compressor. This number is always greater than 1.0. To produce the increase in pressure, the compressor must perform work on the flow.

What is the meaning of surge line?

Surge is defined as the operating point at which centrifugal compressor peak head capability and minimum flow limits are reached. A collection of surge points during varying compressor speed or varying inlet gas angle is fitted as surge line.

How much RPM does a turbocharger have?

The turbine in the turbocharger spins at speeds of up to 150,000 rotations per minute (rpm) — that’s about 30 times faster than most car engines can go. And since it is hooked up to the exhaust, the temperatures in the turbine are also very high.

How many types of turbos are there?

Types of Turbine Geometry. There are three types of turbines suitable for exhaust gas turbochargers: radial-flow, axial-flow and mixed-flow, Figure 22 [2541] . The mixed flow turbine has characteristics between the radial and axial turbines.

How bad is compressor surge?

The difference is that compressor surge occurs while you’re on the throttle and compressor blades in the turbo stalls. This causes loss of boost pressure, thus loss of horsepower, probably bad AFR. Over time, repeated compressor surges damages the bearings in the turbo and it goes kaputz.

How are Compressor maps used in industrial processes?

Compressor maps are an integral part of predicting the performance of gas turbine and turbocharged engines, both at design and off-design conditions. They also serve a critical purpose in selecting the correct compressors for industrial processes.

What does the compressor map on a BorgWarner mean?

“A compressor map shows mass flow, pressure ratio, speed, and efficiency. It can be thought of as a dyno output/chart for the compressor stage independent of the engine it’s run on” says Seth Temple Applications Engineer for BorgWarner.

Why do you use corrected parameters on a compressor map?

The basis for using corrected parameters on the map is mach number kinematic similarity. Corrected flow and speed define mach numbers through the compressor and flow angles onto the blades using velocity triangles. Velocity triangles allow flows to be transferred between different reference frames.

How is the vertical axis of a compressor calculated?

The vertical axis represents the pressure ratio of the compressor. It is calculated by taking the absolute outlet pressure and dividing by the absolute inlet pressure. (Note, most gauges read in gauge pressure i.e. zero psi at atmospheric when it is actually around 14.7 or so psi.)