The county executive of one of the richest jurisdictions in the United States went begging door-to-door yesterday, seeking money to feed the hungry.

Charles W. Gilchrist, accompanied by Rep. Michael Barnes (D-Montgomery) and a group of church leaders who were kicking off a Thanksgiving drive to raise money to fight hunger in their home county and overseas.

"You can live in Montgomery County and never realize that there are people here that really are hungry," Barnes said after he and Gilchrist knocked on the door of Francesca Avelleyra's house on Piney Branch Parkway in Silver Spring and collected a $10 donation.

Yesterday's fund raising, preceded by a press conference, was largely ceremonial, but Gilchrist and Barnes are expected to join about 15,000 other volunteers this weekend for serious door-to-door solicitation for money, as they did in a similar Montgomery County Hunger Relief drive that raised $33,702 last Thanksgiving.

In a separate Thanksgiving relief drive in Montgomery, about half the 1,100 students at Woodward High School in Rockville went without pizza in the school cafeteria yesterday and they gave their lunch money to World Vision to fight hunger in Ethiopia.

Senior David Rifkind, who organized the fast, said at least $2,000 had been raised.

"We decided it was time we did something," he said, adding that the students wanted "to set an example, and to let the community and the nation know we are not the 'me' generation that we were labeled during the election."

At yesterday's press conference, Gilchrist called on county residents to "recognize the tremendous need, in the world and in the county, of people who don't have enough food to eat."

Despite an average disposable income last year of $39,440 per family, officials say the county has a large number of people who cannot afford to buy enough food. The 1980 census showed that more than 24,000 of the county's 564,507 residents were at or below the national poverty level, which was $7,412 for a family of four.

County officials, church groups and social workers say requests for food assistance are increasing. Officials said the county's food hot line received an average of 60 calls a day from people looking for food between January and September.

The county established the hot line after a report earlier showed a sharp rise in the demand for emergency food and money for food. Last year, public and private relief organizations in the county distributed food or money for food 21,118 times, a sharp increase over the 7,878 deliveries in 1980.

The Montgomery County Community Ministry, an organization of church groups, said local relief groups have increased food aid by 20 percent in the last year and are still unable to meet the demand. These groups made 22,606 emergency deliveries of food to the needy in the first six months of this year.

The Rev. Lon Dring, director of the Community Ministry, said one-third of the money collected by volunteers over the Thanksgiving weekend will go to help the hungry in Montgomery County, a third will go to the hungry in the District of Columbia, and a third will be used to feed hungry people overseas. The volunteers are hoping to raise $50,000, he said.