Analysis of the dynamics of two-way hydropercussion systems. Part II: Influence of design factors and their interaction with rocks

Selection procedure for hydraulic impact system parameters

“…Figure 1 shows a schematics of the hydraulic impact system, including the fluid feed unit 1 (pump P, safety valve SV, pressure line PL and drain line DL), impact unit 2 (impact assembly IA and distributor D with back coupling, as well as the forcing accumulator FA and discharge accumulator DA) and the bit holdback H. This is the bilateral system with the controlled forward stroke cell (cell B) and the holdback bit. The operating cycle has the same structure as in [2]. The difference is the backward stroke cell A is always connected with the pressure line PL and, in this case, the area B S in this scheme is equal to the sum of the areas B S and A S in the scheme in Fig.…”

“…Charge pressure of the pressure and drainage accumulator p 10 , p 20 Pa Bit velocity recovery coefficient R - 1 The coefficient κ depends on the fluid flow regime and the Reynolds number. 2 The notion of the hydraulic capacitance is borrowed from the theory of hydraulic circuits [5].…”

“…Some of the parameters should be constant, e.g. the parameters at the pump, distributor, pressure and drain lines, and pressure and drainage accumulators may be: q 0 , p, η 0 , m, x [2] , S f , m V , m c 5 , S C , r 3 , r 4 , r 7 , S V f , r 1 , r 2 , h с 1 , h с 2 , L 1 , L 2 , V 10 , V 20 , p 10 , p 20 , (7) while the other parameters:…”

“…The authors have studied numerically the dynamics of bilateral hydraulic impact systems in the wide range of dimensional parameters-similarity criteria [1,2]. The similarity criteria make it possible to have an image concept of properties and capacities of the bilateral hydraulic impact systems, define their operating regimes and the domain where the systems enter the single blow limit cycle, and estimate the effect of the design parameters on the system performance.…”

A model-based methodology for rapid designing of hydraulic breakers

“…Gorodilov again (2000) analyzed the working cycle of a hydraulic breaker using similarity criteria, and the analogy method in which the factors defining the system are not considered separately, but in some combinations in the form of total effects, then deepening, in a subsequent work (2002), also the effect of an ideal distributor. In addition Gorodilov (2012Gorodilov ( , 2013 proposed a mathematical model of a two-way hydropercussion.…”