ELSEVIER Powder Technology 84 (1995) 57--64 POWDER TECHNOLOGY Water-only performance of proportioning jet pumps for transportation of solids D. Wang, P.W. Wypych Department of Mechanical Engineedn& University of Wollongong Wollongon~ NSW 2522 Australia Received 12 July 1994; revised 5 December 1994 hydraulic Abstract Experimental observations of water-only performance and pressure losses have been made for a proportioning jet pump feeder with eighteen different configurations and designs. Based on these results, the influence of structure and configuration on the performance of jet pump feeder has been investigated. Optimal configuration and geometrical parameters have been recommended for design practice. Formulae for performance prediction have been proposed and verified. Keywords: Water-only performance; Pressure loss; Proportioning jet pumpfeeder; Design practice 1. Introduction Jet pumps, particularly those with all the wearing surfaces made of alloy cast iron, ceramics, or other wear-resistant alloys for abrasive applications, are prob- ably the most desirable type of pump to be used as a feeder in the hydraulic transportation of solids. The reasons are simplicity in structure, absence of moving parts, reliability and low capital cost, convenience of operation and maintenance and wear-resistant. These features more than compensate for the relatively poor efficiency of this type of feeder. Furthermore, it possesses the ability to be self-regulating, that is, if it is overloaded, it will reject water and material back through the suction port until the overload is eliminated. A conventional jet pump comprises a central convergent driving nozzle and an annular suction passage. The difference in structure between a conventional jet pump and a pro- portioning jet pump shown in Fig. 1, is that the pro- It ~ q Fig. 1. General configuration of a proportioning jet pump. 1, spindle nozzle; 2, suction chamber; 3, throat tube; 4, diffuser. 0032-5910/95/$09.50 © 1995 Elsevier Science S.A. All rights reserved SSDI 0032-5910(94)02965-Q portioning jet pump consists of a spindle nozzle, the necessary sealing and an adjusting device. Apart from all the advantages of the conventional jet pump, the proportioning jet pump possesses the additional ca- pability of being able to optimize performance char- acteristics by moving the spindle back and forth manually or mechanically to suit the operating conditions of the hydraulic transportation system. Unfortunately, this type of pump has not received extensive investigation and application in engineering practice, and no design pro- cedure and performance prediction method as yet have been published [1-4]. There also is a shortage of experimental data reported in the literature regarding the influence of configurations on performance char- acteristics. Therefore, it is of great importance to mon- itor the water-only performance of this type of jet pump and investigate the effect of geometrical parameters so that performance prediction models can be formulated and strategies to improve performance characteristics can be determined. 2. Test rig and experimental procedure 2.1. Test rig Fig. 2 shows the layout of the test rig employed to monitor the performance characteristics of the pro- portioning jet pump with different configurations. This rig consists of various proportioning jet pumps, cen- trifugal pumps to supply primary jet flow and secondary