Numerical Study of Heat Transfer in Trefoil Buried Cable with Fluidized Thermal Backfill and Laying Parameter Optimization

<table class="fixed-width table-group" id="tab5"><tr><td><table class="table"><colgroup><col style="width:8.44em"/><col style="width:3.77em"/><col style="width:3.77em"/><col style="width:3.29em"/><col style="width:3.54em"/><col style="width:5.43em"/></colgroup><tr><td class="thead-hr" colspan="6"><hr/></td></tr><tr class="thead"><td class="align_left">FTB laying model</td><td class="align_center"><svg height="9.14241pt" id="M75" style="vertical-align:-3.1815pt" version="1.1" viewbox="-0.0498162 -5.96091 9.8741 9.14241" width="9.8741pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M352 391C352 416 319 448 267 448C236 448 173 423 147 400C107 364 96 332 96 304C96 248 143 210 193 181C241 153 258 124 258 100C258 72 232 38 184 38C151 38 107 66 81 108C77 114 64 116 55 111C34 99 23 84 23 65C23 29 81 -12 134 -12C220 -12 325 61 325 141C325 184 297 215 234 256C194 282 161 309 161 346C161 380 188 401 217 401C255 401 279 380 301 353C308 344 313 341 325 347C341 355 352 371 352 391Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,4.81,3.132)"><path d="M389 0V32C297 38 291 46 291 118V635C234 613 175 595 109 583V556L161 554C203 552 207 547 207 497V118C207 46 201 38 110 32V0H389Z"></path></g></svg> [m]</td><td class="align_center"><svg height="9.14241pt" id="M76" style="vertical-align:-3.1815pt" version="1.1" viewbox="-0.0498162 -5.96091 9.8741 9.14241" width="9.8741pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M352 391C352 416 319 448 267 448C236 448 173 423 147 400C107 364 96 332 96 304C96 248 143 210 193 181C241 153 258 124 258 100C258 72 232 38 184 38C151 38 107 66 81 108C77 114 64 116 55 111C34 99 23 84 23 65C23 29 81 -12 134 -12C220 -12 325 61 325 141C325 184 297 215 234 256C194 282 161 309 161 346C161 380 188 401 217 401C255 401 279 380 301 353C308 344 313 341 325 347C341 355 352 371 352 391Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,4.81,3.132)"><path d="M414 144C384 79 371 75 317 75H135L276 221C367 316 408 376 408 465C408 570 327 635 237 635C179 635 131 609 100 575L42 494L67 471C94 510 138 565 205 565C277 565 321 517 321 435C321 348 258 270 195 195C146 137 88 81 33 26V0H411C423 44 433 88 446 135L414 144Z"></path></g></svg> [m]</td><td class="align_center"><svg height="9.49473pt" id="M77" style="vertical-align:-0.2063999pt" version="1.1" viewbox="-0.0498162 -9.28833 3.60972 9.49473" width="3.60972pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M238 681C243 705 239 712 230 712C217 712 156 682 75 674L70 648H105C148 648 153 641 144 598L39 110C18 11 35 -12 55 -12C90 -12 166 36 221 103L205 125C174 93 130 65 118 65C112 65 108 68 114 96L238 681Z"></path></g></svg> [m]</td><td class="align_center"><svg height="9.49473pt" id="M78" style="vertical-align:-0.2063999pt" version="1.1" viewbox="-0.0498162 -9.28833 6.83278 9.49473" width="6.83278pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M499 88L487 113C459 86 422 65 413 65C403 65 403 74 409 98L461 318C487 426 460 448 431 448C408 448 383 441 352 424C305 398 223 344 157 257H155L243 674C249 702 249 712 240 712C227 712 170 680 87 673L82 648H117C155 648 162 644 150 590L23 -4L30 -12C55 -4 81 3 105 8C113 53 131 150 143 187C199 281 323 387 372 387C390 387 393 369 380 311L328 86C313 19 319 -12 347 -12C379 -12 442 24 499 88Z"></path></g></svg> [m]</td><td class="align_center"><svg height="11.8174pt" id="M79" style="vertical-align:-3.1815pt" version="1.1" viewbox="-0.0498162 -8.6359 27.011 11.8174" width="27.011pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M686 28C612 35 607 44 591 112C563 234 541 360 519 489L489 666L457 658L147 121C100 40 89 36 24 28L17 0H240L250 28C168 34 159 41 190 101L262 237H482C495 180 503 137 510 91C517 47 514 35 441 28L433 0H677L686 28ZM475 280H285L429 541H431L475 280Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,10.244,3.132)"><path d="M502 500C497 551 492 613 491 650H43V617C122 612 130 606 130 521V129C130 45 122 38 41 33V0H319V33C227 38 217 45 217 129V305H319C411 305 413 295 427 225H461V421H427C414 357 411 348 319 348H217V580C217 609 219 612 250 612H330C401 612 423 605 439 578C452 557 458 539 467 496L502 500Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,15.158,3.132)"><path d="M601 496C596 555 591 627 591 675H567C551 656 544 650 516 650H120C91 650 79 651 64 675H41C38 619 34 555 29 492H63C75 537 83 566 96 582C110 604 128 612 207 612H272V126C272 46 264 38 170 33V0H464V33C368 38 359 48 359 126V612H430C502 612 520 605 535 582C547 566 556 541 567 492L601 496Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,20.873,3.132)"><path d="M384 354C435 370 515 408 515 502C515 549 494 593 459 616C426 639 384 650 308 650H45V618C127 613 130 606 130 524V127C130 45 125 38 37 33V0H262C342 0 409 12 461 40C521 73 558 124 558 192C558 295 481 336 384 352V354ZM217 365V556C217 587 221 597 229 604C238 611 261 615 288 615C382 615 421 558 421 490C421 406 374 365 266 365H217ZM217 327H264C384 327 457 284 457 183C457 80 383 38 301 38C235 38 217 55 217 127V327Z"></path></g></svg> [m<sup>2</sup>]</td></tr><tr><td class="thead-hr" colspan="6"><hr/></td></tr><tr><td class="align_left">FTB (Parabolic)</td><td class="align_center">3.5<svg height="11.4488pt" id="M80" style="vertical-align:-5.48789pt" version="1.1" viewbox="-0.0498162 -5.96091 7.9194 11.4488" width="7.9194pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M393 379C402 394 400 411 393 422C384 437 365 448 348 448C301 448 237 372 186 285H182L193 335C210 408 205 448 178 448C150 448 80 402 29 344L45 321C80 355 114 373 122 373C128 373 130 365 124 330C106 228 76 98 50 -5L57 -12C82 -5 112 3 132 6L172 203C196 256 234 304 254 329C275 355 293 367 306 367C318 367 330 360 342 348C347 343 355 343 365 350S386 367 393 379Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,4.901,3.132)"><path d="M139 535C170 535 192 560 192 589C192 621 169 644 140 644C109 644 86 621 86 589C86 560 110 535 139 535ZM35 387C99 379 105 374 105 307V114C105 22 103 -35 96 -78C89 -113 82 -131 70 -146C55 -162 30 -174 -1 -181C-16 -184 -23 -192 -23 -207C-23 -232 0 -253 15 -253C24 -253 33 -249 41 -242C63 -223 127 -148 162 -48C181 6 186 47 186 117V453C143 435 93 422 36 414L35 387Z"></path></g></svg></td><td class="align_center">0.2</td><td class="align_center">8<svg height="11.4488pt" id="M81" style="vertical-align:-5.48789pt" version="1.1" viewbox="-0.0498162 -5.96091 7.9194 11.4488" width="7.9194pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M393 379C402 394 400 411 393 422C384 437 365 448 348 448C301 448 237 372 186 285H182L193 335C210 408 205 448 178 448C150 448 80 402 29 344L45 321C80 355 114 373 122 373C128 373 130 365 124 330C106 228 76 98 50 -5L57 -12C82 -5 112 3 132 6L172 203C196 256 234 304 254 329C275 355 293 367 306 367C318 367 330 360 342 348C347 343 355 343 365 350S386 367 393 379Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,4.901,3.132)"><path d="M139 535C170 535 192 560 192 589C192 621 169 644 140 644C109 644 86 621 86 589C86 560 110 535 139 535ZM35 387C99 379 105 374 105 307V114C105 22 103 -35 96 -78C89 -113 82 -131 70 -146C55 -162 30 -174 -1 -181C-16 -184 -23 -192 -23 -207C-23 -232 0 -253 15 -253C24 -253 33 -249 41 -242C63 -223 127 -148 162 -48C181 6 186 47 186 117V453C143 435 93 422 36 414L35 387Z"></path></g></svg></td><td class="align_center">/</td><td class="align_center">0.351</td></tr><tr><td class="align_left">FTB (Flat)</td><td class="align_center">/</td><td class="align_center">/</td><td class="align_center">/</td><td class="align_center">0.4</td><td class="align_center">0.560</td></tr><tr class="table-tr"><td colspan="6"><hr class="tbody-hr"/></td></tr></table></td></tr></table>

<div>Geometric parameters for flat-type FTB and parabolic-type FTB trefoil buried cables.</div>

Mathematical Problems in Engineering

tab5

Table 5

Table 5: Numerical Study of Heat Transfer in Trefoil Buried Cable with Fluidized Thermal Backfill and Laying Parameter Optimization 