【Mechanical Equipment Technology Exchange Edition】Mechanical Equipment 【Daily Question】201200115

The magnitude of the reheat coefficient is related to the following factors: (1) the efficiency of each stage in a multi-stage steam turbine. If the stage efficiency is 1, meaning there are no losses in any stage, then there are also no losses available for subsequent stages, and thus the reheat coefficient α = 0. The lower the stage efficiency, the greater the losses, and the more of the output is utilized by subsequent stages, resulting in a higher α value. (2) The number of stages in a multi-stage steam turbine. The more stages there are, the greater the likelihood that the loss from the previous stage will be utilized by the subsequent stages, and the larger the share of utilization, so the α value will increase. (3) Initial parameters at various levels. Initially, when the temperature is higher and the initial pressure is lower, the specific entropy of the initial state is larger, causing the expansion process to take place in the region where the pressure difference is greater between the isobaric lines, resulting in a larger value for α. Furthermore, since the degree of isobaric line expansion is greater in the superheated steam region and smaller in the wet steam region, it is in the superheated region. High value, humid zone. The value is small.

(1) The efficiency of each stage of a multi-stage steam turbine. If the stage efficiency is 1, meaning there are no losses in any stage, then there are also no losses available for subsequent stages, and thus the reheat coefficient α = 0. The lower the stage efficiency, the greater the losses, and more of the energy is utilized in subsequent stages, resulting in a higher α value. (2) The number of stages in a multi-stage steam turbine. The more stages there are, the greater the likelihood that the loss from the previous stage will be utilized by the subsequent stages, and the larger the share of utilization, so the α value will increase. (3) Initial parameters at various levels. Initially, when the temperature is higher and the initial pressure is lower, the specific entropy of the initial state is larger, causing the expansion process to take place in the region where the pressure difference is greater between the isobaric lines, resulting in a larger value for α. Furthermore, since the degree of isobaric line expansion is greater in the superheated steam region and smaller in the wet steam region, it is in the superheated region. High value, humid zone. The value is small.

1. The efficiency of each stage of a multi-stage steam turbine. The lower the stage efficiency, the greater the losses, and the more of the output is utilized by subsequent stages, resulting in a higher α value. 2. The number of stages in a multi-stage steam turbine. The more stages there are, the greater the likelihood that the loss from the previous stage will be utilized by the subsequent stages, and the larger the share utilized will be; as a result, the α value will increase. 3. Initial parameters at various levels. Initially, when the temperature is higher and the initial pressure is lower, the specific entropy of the initial state is larger, causing the expansion process to take place in the region where the pressure difference is greater between the isobaric lines, resulting in a larger value for α. Furthermore, since the degree of isobaric line expansion is greater in the superheated steam region and smaller in the wet steam region, it is in the superheated region. High value, humid zone. The value is small.

1) Efficiency of each stage of a multi-stage steam turbine. If the stage efficiency is 1, meaning there are no losses in any stage and no losses remain available for subsequent stages, then the reheat coefficient β is 0. The lower the stage efficiency, the greater the losses, and the more of the energy is available for later stages, resulting in a higher value for β. 2) The number of stages in a multi-stage steam turbine. The more stages there are, the greater the likelihood that the loss from the previous stage will be utilized compared to those from later stages, and the larger the share utilized will be; as a result, the β value increases. 3) Initial parameters at various levels. When the exit temperature is higher and the initial pressure is lower, the specific entropy of the initial state increases, causing the expansion process to approach the region of greater expansion during isobaric stages, resulting in a larger β value. Furthermore, since the expansion degree of the compressor is greater in the superheated steam zone and smaller in the wet steam zone, the β value is larger in the superheated zone and smaller in the wet steam zone.

The ratio of the total sum of isentropic enthalpy drops at all levels to the excess value of the overall isentropic enthalpy drop, divided by the overall isentropic enthalpy drop.

(1) The efficiency of each stage of a multi-stage steam turbine. (2) The number of stages in a multi-stage steam turbine. (3) Initial parameters at various levels.

The magnitude of the reheat coefficient is related to the following factors: (1) the efficiency of each stage in a multi-stage steam turbine. If the stage efficiency is 1, meaning there are no losses in any stage, then there are also no losses available for subsequent stages, and thus the reheat coefficient α = 0. The lower the stage efficiency, the greater the losses, and the more of the output is utilized by subsequent stages, resulting in a higher α value. (2) The number of stages in a multi-stage steam turbine. The more stages there are, the greater the likelihood that the loss from the previous stage will be utilized by the subsequent stages, and the larger the share of utilization, so the α value will increase. (3) Initial parameters at various levels. Initially, when the temperature is higher and the initial pressure is lower, the specific entropy of the initial state is larger, causing the expansion process to take place in the region where the pressure difference is greater between the isobaric lines, resulting in a larger value for α. Furthermore, since the degree of isobaric line expansion is greater in the superheated steam region and smaller in the wet steam region, it is in the superheated region. High value, humid zone. The value is small.

The magnitude of the reheat coefficient is related to the following factors: (1) the efficiency of each stage in a multi-stage steam turbine. If the stage efficiency is 1, meaning there are no losses in any stage, then there are also no losses available for subsequent stages, and thus the reheat coefficient α = 0. The lower the stage efficiency, the greater the losses, and the more of the output is utilized by subsequent stages, resulting in a higher α value. (2) The number of stages in a multi-stage steam turbine. The more stages there are, the greater the likelihood that the loss from the previous stage will be utilized by the subsequent stages, and the larger the share of utilization, so the α value will increase. (3) Initial parameters at various levels. Initially, when the temperature is higher and the initial pressure is lower, the specific entropy of the initial state is larger, causing the expansion process to take place in the region where the pressure difference is greater between the isobaric lines, resulting in a larger value for α. Furthermore, since the degree of isobaric line expansion is greater in the superheated steam region and smaller in the wet steam region, it is in the superheated region. High value, humid zone. The value is small.

The magnitude of the reheat coefficient is related to the following factors: (1) the efficiency of each stage in a multi-stage steam turbine. If the stage efficiency is 1, meaning there are no losses in any stage, then there are also no losses available for subsequent stages, and thus the reheat coefficient α = 0. The lower the stage efficiency, the greater the losses, and the more of the output is utilized by subsequent stages, resulting in a higher α value. (2) The number of stages in a multi-stage steam turbine. The more stages there are, the greater the likelihood that the loss from the previous stage will be utilized by the subsequent stages, and the larger the share of utilization, so the α value will increase. (3) Initial parameters at various levels. Initially, when the temperature is higher and the initial pressure is lower, the specific entropy of the initial state is larger, causing the expansion process to take place in the region where the pressure difference is greater between the isobaric lines, resulting in a larger value for α. Furthermore, since the degree of isobaric line expansion is greater in the superheated steam region and smaller in the wet steam region, it is in the superheated region. High value, humid zone. The value is small.

The magnitude of the reheat coefficient is related to the following factors: (1) the efficiency of each stage in a multi-stage steam turbine. If the stage efficiency is 1, meaning there are no losses in any stage, then there are also no losses available for subsequent stages, and thus the reheat coefficient α = 0. The lower the stage efficiency, the greater the losses, and the more of the output is utilized by subsequent stages, resulting in a higher α value. (2) The number of stages in a multi-stage steam turbine. The more stages there are, the greater the likelihood that the loss from the previous stage will be utilized by the subsequent stages, and the larger the share of utilization, so the α value will increase. (3) Initial parameters at various levels. Initially, when the temperature is higher and the initial pressure is lower, the specific entropy of the initial state is larger, causing the expansion process to take place in the region where the pressure difference is greater between the isobaric lines, resulting in a larger value for α. Furthermore, since the degree of isobaric line expansion is greater in the superheated steam region and smaller in the wet steam region, it is in the superheated region. High value, humid zone. The value is small.