Calculate the pump specific speed of the pump of Example 14–11 at its best efficiency point. Provide answers in both dimensionless form and in customary U.S. units. What kind of pump is it?

Data from Example 14-11

After graduation, you work for a pump manufacturing company. One of your company’s best-selling products is a water pump, which we shall call pump A. Its impeller diameter is D_A = 6.0 cm, and its performance data when operating at ṅ_A = 1725 rpm (ω_A = 180.6 rad/s) are shown in Table 14–2. The marketing research department is recommending that the company design a new product, namely, a larger pump (which we shall call pump B) that will be used to pump liquid refrigerant R-134a at room temperature. The pump is to be designed such that its best efficiency point occurs as close as possible to a volume flow rate of V̇_B = 2400 cm3/s and at a net head of H_B = 450 cm (of R-134a). The chief engineer (your boss) tells you to perform some preliminary analyses using pump scaling laws to determine if a geometrically scaled-up pump could be designed and built to meet the given requirements. 

(a) Plot the performance curves of pump A in both dimensional and dimensionless form, and identify the best efficiency point.

(b) Calculate the required pump diameter D_B, rotational speed ṅ_B, and brake horsepower bhp_B for the new product.