Heat Transfer

Overview

Heat transfer is the study of how thermal energy moves by conduction, convection, and radiation across solids, fluids, and interfaces. In process, energy, and mechanical engineering, these calculations govern exchanger sizing, utility demand, thermal safety margins, and lifecycle operating cost. This category combines correlation-based design tools and thermal-geometry utilities so analysts can move from quick screening to detailed rating with consistent methods.

The common framework is the dimensionless formulation of transport behavior: Nu, Re, Pr, Gr, and Ra for convection; resistance networks for conduction; and emissive/absorptive exchange for radiation. Many workflows map through h = \frac{Nu\,k}{L}, \qquad Q = UA\Delta T_{lm}, \qquad q''=-k\nabla T, then add geometry, entry-length, wall-property, and phase-change corrections based on operating regime. This is why correlation selection and method validity ranges matter as much as raw equation evaluation.

Implementation is built primarily on the Python ht library and its submodules (for example ht.conv_internal, ht.boiling_flow, ht.condensation, ht.conduction, and ht.hx). The library packages literature correlations and exchanger design utilities behind consistent APIs, which makes it practical for reproducible spreadsheet and scripting workflows.

Air cooler and exchanger-core workflows focus on crossflow correction factors, fin efficiency, and thermal driving-force checks used in preliminary and detailed rating. Air Cooler functions include AIR_NOISE_GPSA, AIR_NOISE_MUKHERJEE, DP_ESDU_HIGH_FIN, DP_ESDU_LOW_FIN, ESDU_TUBE_ROW_CORR, FIN_EFF_KERN_KRAUS, FT_AIRCOOLER, H_BRIGGS_YOUNG, H_ESDU_HIGH_FIN, H_ESDU_LOW_FIN, H_GANGULI_VDI, LMTD, WALL_FACTOR. Core functions include CC_HX_TEMP_CHECK, FIN_EFFICIENCY_KK, IS_HEATING_PROPERTY, IS_HEATING_TEMP, WALL_FACTOR_FD, WALL_FACTOR_NU. Hx functions include BAFFLE_THICKNESS, BUNDLE_FROM_TUBES, CALC_CMAX, CALC_CMIN, CALC_CR, CHECK_TUBING_TEMA, D_BAFFLE_HOLES, D_FOR_NTUBES_VDI, DBUNDLE_MIN, DBUNDLE_NT_HEDH, DBUNDLE_NT_PHADK, EFF_FROM_NTU, EFF_NTU_METHOD, F_LMTD_FAKHERI, L_UNSUPPORTED_MAX, NTU_FROM_EFF, NTU_FROM_P_BASIC, NTU_FROM_P_E, NTU_FROM_P_PLATE, NTU_FROM_UA, NTUBES, NTUBES_HEDH, NTUBES_PHADKEB, NTUBES_VDI, P_NTU_METHOD, SHELL_CLEARANCE, TEMP_EFF_BASIC, TEMP_EFF_PLATE, TEMP_EFF_TEMA_E, UA_FROM_NTU.

Phase-change and two-phase correlations cover flow boiling, nucleate boiling, plate boiling, in-tube condensation, and mixed-regime convection where liquid-vapor interactions dominate coefficient behavior. Boiling Flow functions include CHEN_BENNETT, CHEN_EDELSTEIN, COOPER, FORSTER_ZUBER, LAZAREK_BLACK, LI_WU, LIU_WINTERTON, LOCKHART_XTT, SUN_MISHIMA, THOME, TO_SOLVE_Q_THOME, TURBULENT_DITTUS, TURBULENT_GNIEL, YUN_HEO_KIM. Boiling Nucleic functions include BIER, GORENFLO, H_NUCLEIC, H_NUCLEIC_METHODS, HEDH_MONTINSKY, HEDH_TABOREK, MCNELLY, MONTINSKY, QMAX_BOIL_METHODS, QMAX_BOILING, ROHSENOW, SERTH_HEDH, STEPHAN_ABDELSALAM, ZUBER. Boiling Plate functions include H_BOIL_HAN_LEE_KIM, H_BOIL_HANLEEKIM, H_BOIL_HUANG_SHEER, H_BOIL_HUANGSHEER, H_BOIL_LEE_KANG_KIM, H_BOIL_LEEKANGKIM, H_BOILING_AMALFI, H_BOILING_YAN_LIN, THERMAL_DIFFUSIVITY. Condensation functions include AKERS_DEANS_CROSSER, BOYKO_KRUZHILIN, CAVALLINI_SMITH_Z, CAVALLINI_SZ, H_KINETIC, NUSSELT_LAMINAR, SHAH. Conv Two Phase functions include AGGOUR, DAVIS_DAVID, ELAMVALUTHI_SRIN, GROOTHUIS_HENDAL, H_TWO_PHASE, H_TWO_PHASE_METHODS, HUGHMARK, KNOTT, KUDIRKA_GROSH_MCF, LAMINAR_ENTRY_ST, MARTIN_SIMS, RAVIPUDI_GODBOLD.

Single-phase convection utilities span external forced convection, natural convection in enclosed and immersed geometries, internal pipe/duct relations, jacketed vessels, packed beds, plate channels, supercritical fluids, and tube-bank bundles. Conv External functions include NU_CYL_CB, NU_CYL_PL62, NU_CYL_PL64, NU_CYL_SG, NU_CYL_WHITAKER, NU_CYL_ZUKAUSKAS, NU_CYLINDER_FAND, NU_CYLINDER_MCADAMS, NU_EXT_CYL, NU_EXT_CYL_METHODS, NU_EXT_HORZ_METHODS, NU_EXT_HORZ_PLATE, NU_HORZ_LAM_BAEHR, NU_HORZ_LAM_COZOE, NU_HORZ_TURB_KREITH, NU_HORZ_TURB_SCHL. Conv Free Enclosed functions include NU_RA_HOLLANDS, NU_RA_HOLLINGHERWIG, NU_RA_PROBERT, NU_VERT_THESS, NU_VHELIX_ALI, NU_VHELIX_PRR, RAC_RAYLEIGH, RAC_RAYLEIGH_DISK. Conv Free Immersed functions include NU_COIL_XIN_EBADIAN, NU_FREE_HPLATE, NU_FREE_HPLATE_METH, NU_FREE_VPLATE, NU_FREE_VPLATE_METH, NU_HCYL_CHURCHILL, NU_HCYL_KUEHNGOLD, NU_HCYL_METHODS, NU_HCYL_MORGAN, NU_HORIZ_CYL, NU_HPLATE_MCADAMS, NU_HPLATE_ROHSENOW, NU_HPLATE_VDI, NU_SPHERE_CHURCHILL, NU_VCYL_ALARABI, NU_VCYL_CARNEMORGAN, NU_VCYL_EIGENSON, NU_VCYL_GRIFFITHS, NU_VCYL_HANESIAN, NU_VCYL_JAKOB, NU_VCYL_KREITH, NU_VCYL_MCADAMS, NU_VCYL_METHODS, NU_VCYL_POPIEL, NU_VCYL_TOULOUKIAN, NU_VERT_CYL, NU_VPLATE_CHURCHILL. Conv Internal functions include HEL_TURB_NU_MORI, HEL_TURB_NU_SCHM, HEL_TURB_NU_XIN, LAM_ENTRY_BAEHR, LAM_ENTRY_HAUSEN, LAM_ENTRY_SEIDER, LAMINAR_Q_CONST, LAMINAR_T_CONST, MORIMOTO_HOTTA, NU_CONV_INT_METHODS, NU_CONV_INTERNAL, NU_LAM_RECT_SHAN, TURB_BHATTI_SHAH, TURB_CHURCHILL, TURB_COLBURN, TURB_DIPPREY, TURB_DITTUS, TURB_DREXEL, TURB_ENTRY_HAUSEN, TURB_ESDU, TURB_FRIEND, TURB_GNIEL_S1, TURB_GNIEL_S2, TURB_GNIELINSKI, TURB_PETUKHOV, TURB_PRANDTL, TURB_SIEDER, TURB_VON_KARMAN, TURB_WEBB. Conv Jacket functions include LEHRER, STEIN_SCHMIDT. Conv Packed Bed functions include NU_ACHENBACH, NU_KTA, NU_PACKED_BED_GN, NU_WAKAO_KAGEI. Conv Plate functions include FRIC_PLATE_MARTIN99, FRIC_PLATE_MARTINV, NU_PLATE_KHAN_KHAN, NU_PLATE_KUMAR, NU_PLATE_MARTIN, NU_PLATE_MULEYMANG. Conv Supercritical functions include NU_BISHOP, NU_BRINGER_SMITH, NU_GORBAN, NU_GRIEM, NU_GUPTA, NU_JACKSON, NU_KITOH, NU_KRASN_PROTO, NU_KRASNOSH_PROTO, NU_KRASNOSHCHEKOV, NU_MCADAMS, NU_MOKRY, NU_ORNATSKY, NU_PETUKHOV, NU_SHITSMAN, NU_SWENSON, NU_XU, NU_YAMAGATA, NU_ZHU. Conv Tube Bank functions include CTB_BAFFLE_CORR, CTB_BAFFLE_LEAK, CTB_BUNDLE_BYPASS, CTB_DP_KERN, CTB_DP_ZUKAUSKAS, CTB_ESDU_ANG_CORR, CTB_ESDU_ROW_CORR, CTB_HORNER, CTB_LAMINAR_CORR, CTB_NU_ESDU_73031, CTB_NU_GRIMISON, CTB_NU_HEDH, CTB_NU_ZUK_BEJAN, CTB_UNEQUAL_BAFFLE, CTB_WALL_FACTOR, CTB_ZUK_ROW_CORR.

Solid conduction, insulation properties, and radiation utilities provide the complementary static- and boundary-condition tools needed to close exchanger and thermal-loss studies. Conduction functions include ACOSH, CYL_HEAT_TRANSFER, K_TO_R, K_TO_R_VALUE, K_TO_THERM_RESIST, LEGACY_CYL_HT, LEGACY_K_THERM_RES, LEGACY_S_PIPE_ECC, LEGACY_S_PIPE_NORM, LEGACY_S_PIPE_PAIR, LEGACY_S_PIPE_PLANE, LEGACY_S_PIPE_PLNS, LEGACY_S_SPH_PLANE, LEGACY_THERM_RES_K, LOG, R_CYLINDER, R_TO_K, R_VALUE_TO_K, S_PIPE_ECC_TO_PIPE, S_PIPE_NORM_PLANE, S_PIPE_TO_PIPE, S_PIPE_TO_PLANE, S_PIPE_TWO_PLANES, S_SPHERE_TO_PLANE, THERM_RESIST_TO_K. Insulation functions include ASHRAE_K, CP_MATERIAL, INTERP, K_MATERIAL, NEAREST_MATERIAL, REFRACTORY_VDI_CP, REFRACTORY_VDI_K, RHO_MATERIAL. Radiation functions include BB_SPECTRAL_RAD, GREY_TRANSMITTANCE, Q_RAD.

Together, these functions support end-to-end thermal engineering workflows: selecting appropriate correlations, checking method assumptions, and connecting coefficient prediction to exchanger-level energy balances. The category is especially useful for comparative studies (method-to-method sensitivity), retrofit screening, and rapid spreadsheet integration where reproducibility and transparent formula provenance are required.