| Webster's Online Dictionary |
| Expressions | Domain | Definition | |
| Effective heat of ablation | Aerospace | Figure of merit for a given material subjected to steady-state heating conditions and undergoing steady-state ablation; the quantity represents the heat dissipated per unit mass of ablated material under specified conditions. (references) | |
| Heat of ablation | Aerospace | 1: A measure of the effective heat capacity of an ablating material, numerically the heating rate input divided by the mass loss rate which results from ablation. In the most general case, heat of ablation is given by (qc + qr - seTw4)/m where qc is convective heat transfer in the absence of ablation; qr is radiative heat transfer from hot gases to ablation material; seTw4 is rate of heat rejection by radiation from external surface of ablation material; and m is rate at which gaseous ablation products are injected into the boundary layer. Heat of ablation is sometimes evaluated neglecting the heat rejected by radiation and as a result unrealistically high heats of ablation are obtained. If qr > seTw4, for moderate values of stream enthalpy hs, heat of ablation is given by Hv + µ (hs - hw) where Hs is heat required to cause a unit weight of mass to be injected into boundary layer; µ is blocking factor with numerical value from about 0.2 to 0.6 depending on material and type of flow; and hw is enthalpy at wall temperature. (references) | |
| 2: Total of the incident heat that an ablative material dissipates per unit mass ablated. See effective heat of ablation. (references) | |||
Source: compiled by the editor from various references; see credits. | Top | ||
