10.2 Laval Nozzle for Attitude Control of Aircraft . . . . . . . . . . . . . . 175
10.2.1 Flow Field Analysis of Laval Nozzle . . . . . . . . . . . . . . 176
10.2.2 Manufacturing Process Technology . . . . . . . . . . . . . . . 184
10.3 Device for Changing Missile Motion Direction by Using
Gas Generator and Transverse Force of Nozzle . . . . . . . . . . . . 185
10.4 Process Technology of Gas Steering Engine . . . . . . . . . . . . . . . 187
10.4.1 Structure and Working Principle . . . . . . . . . . . . . . . . . 187
10.4.2 Redundancy Control . . . . . . . . . . . . . . . . . . . . . . . . . . 188
10.4.3 Fit Clearance Control . . . . . . . . . . . . . . . . . . . . . . . . . 190
10.4.4 Shell Assembly Quality . . . . . . . . . . . . . . . . . . . . . . . 191
10.4.5 Technological Key Problem Test on Symmetry
of Reaction Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
11 Pneumatic Down-the-Hole Hammer . . . . . . . . . . . . . . . . . . . . . . . . 195
11.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
11.2 Principle and Classification of Pneumatic DTH Hammer . . . . . . 198
11.2.1 Classification of Pneumatic DTH Hammer . . . . . . . . . . 198
11.2.2 Principle of Valve-Type Pneumatic DTH Hammer . . . . 200
11.2.3 Valveless Pneumatic DTH Hammer . . . . . . . . . . . . . . . 200
11.2.4 Large Diameter Pneumatic DTH Hammer . . . . . . . . . . 202
11.3 Principle and Parameter Design of Large Diameter
Pneumatic DTH Hammer Impactor . . . . . . . . . . . . . . . . . . . . . 206
11.3.1 Design Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 206
11.3.2 Overall Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207
11.3.3 Selection of Working Parameters . . . . . . . . . . . . . . . . . 208
11.3.4 Calculation Method of Performance Parameters . . . . . . 210
11.3.5 Design of Key Parts . . . . . . . . . . . . . . . . . . . . . . . . . . 218
11.4 Dynamic Process and Theoretical Model of Large
Diameter Pneumatic DTH Hammer . . . . . . . . . . . . . . . . . . . . . 223
11.4.1 Dynamic Process of Large Diameter Pneumatic
DTH Hammer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
11.4.2 Theoretical Model of Large Diameter Pneumatic
DTH Hammer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227
11.4.3 Numerical Calculation of Large Diameter Pneumatic
DTH Hammer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
11.4.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239
11.5 Design of Large Diameter DTH Hammer Bit and Spherical
Tooth Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240
11.5.1 Rock-Breaking Process by Impact . . . . . . . . . . . . . . . . 240
11.5.2 Mechanical Model of Side Tooth of Large
Diameter Pneumatic DTH Hammer Bit . . . . . . . . . . . . 242
11.5.3 Layout Principle of Large Diameter Pneumatic
DTH Hammer Bit . . . . . . . . . . . . . . . . . . . . . . . . . . . 253
Contents
xiii